$299 Gibson tube amp - Made in USA!

Wow I paid $700 for my Mini Z Combo its very Marshally sounding

Heres Buddy W playing his Mini Z http://www.soundclick.com/bands/default.cfm?bandID=304675

I feel like I got ripped off the Gibson GA5 looks real close I hope the GA5 sounds as good as my Mini Z

And I still like the stock speaker with a smith sound enhancer in my Z and I tried a 2x10" Jensen Neo 4 Ohm cab and I thought the stock speaker sounded just as good

Excellent mod. Try a few values or even select a few values with a switch. I think 2.2uF works very well. This reduces the bass frequencies early on in the circuit that when amplified can make the distortion muddy. Also helps to make the amp sound less dark yet it keeps the tone fat.


It would tighten up the bass and reduce hum. It is even worth adding an additional 47uF cap and resistor and change the other 2 first caps for 47uF. This will give it a more modern sound and feel. Easy to try out.

FWIW, The Bad Cat Mini (SE EL84) has huge power caps - something like 220uF, 100uF and 100uF from memory.
Thank you. Do you have photos of those changes? I am trying to get a more modern soundout of the GA-5. Would you happen to have any catalog numbers for those or suggestions of brands?

Thank you. Do you have photos of those changes? I am trying to get a more modern soundout of the GA-5. Would you happen to have any catalog numbers for those or suggestions of brands?
The best way to do this would probably be to copy the Valve Junior Marshall mod changes which I posted earlier in this thread (forum doesn't allow reposting) or get all info directly from the VJ FAQ at SEWATT.com.

Excellent mod. Try a few values or even select a few values with a switch. I think 2.2uF works very well. This reduces the bass frequencies early on in the circuit that when amplified can make the distortion muddy. Also helps to make the amp sound less dark yet it keeps the tone fat.


It would tighten up the bass and reduce hum. It is even worth adding an additional 47uF cap and resistor and change the other 2 first caps for 47uF. This will give it a more modern sound and feel. Easy to try out.

FWIW, The Bad Cat Mini (SE EL84) has huge power caps - something like 220uF, 100uF and 100uF from memory.


Lemme understand - yer saying swap out the stock 22uf filter caps for ones of ungodly huge values, like 47/47/47?

FWIW, two years ago someone wanted to trade me their BC Mini for my '64 stock Champ - fed the Mini a Tele and Strat and thought it was the absolute worse tube amp I'd ever heard: fizzy, icepick treble, farty, absolutely no bottom end, just Icky Horrible ... maybe it was loaded with 220/100/100 caps.

I had read, several years ago, that circuits like these did not sound as good over filtered.

I have a 30uF/16uF/16uF filter caps in my 5E3 clone. If the first filter cap is 16uF the bass is farty at high volume, if it's higher than 30uF or so the amp is to stiff sounding.

These little amps have traditionally used even smaller filter caps.

I've ordered two 10uF caps and will be using them with a 16uF or 20uF first filter cap, pretty similar to the original GA-5.

I'll let you know how it sounds.

I had read, several years ago, that circuits like these did not sound as good over filtered.

I have a 30uF/16uF/16uF filter caps in my 5E3 clone. If the first filter cap is 16uF the bass is farty at high volume, if it's higher than 30uF or so the amp is to stiff sounding.

These little amps have traditionally used even smaller filter caps.

I've ordered two 10uF caps and will be using them with a 16uF or 20uF first filter cap, pretty similar to the original GA-5.

I'll let you know how it sounds.

I'm running with 20/16/16 Atoms and have 10's on order as well.

I have owned a bunch of vintage Gibbies. Stock value filters was always 20-10-10. One day I changed the first cap in a vintage GA-5 to 30uF and it was incredible what a difference that made-I thought the speaker was weak but it was the underfiltered power supply. 10uF is perfect for the other two caps. Just enough filtering to eliminate the crud for a pure clean tone (if you like crud use that little 8uF Sprague, other 8uF caps work fine).

.68 uF is the standard Marshall value bypass cap. That value thins the bass and raises the gain, too much IMO for this amp.

That stock JJ 12AX7 is pretty dark-sounding. I like them for warming up Silverface Fenders. Not so much in a tweed. Rolled a few tubes in the preamp and the clear winner (pun intended) was a Sovtek lps. Really eliminated a lot of the grainy character of the amp. The lps beat the nice vintage Amperex and Tungsol.

Lemme understand - yer saying swap out the stock 22uf filter caps for ones of ungodly huge values, like 47/47/47?
Yes. Compare a Champ 5F1 and a Princeton 5F2-A through the same speaker. 5F2-A sounds much better because 1, it has an extra 16uF making the first cap 32uF and 2, it has a larger OT. Leo would have fitted a larger cap if he could but 32uF is the max when used with a 5Y3 rectifier. Check out the AX84 P1 or the VJ V3 for a well designed power supply.

FWIW, two years ago someone wanted to trade me their BC Mini for my '64 stock Champ - fed the Mini a Tele and Strat and thought it was the absolute worse tube amp I'd ever heard: fizzy, icepick treble, farty, absolutely no bottom end, just Icky Horrible ... maybe it was loaded with 220/100/100 caps.
There are other issues with the BC Mini IMO but those cap values don't make any sense.

Yes. Compare a Champ 5F1 and a Princeton 5F2-A through the same speaker. 5F2-A sounds much better because 1, it has an extra 16uF making the first cap 32uF and 2, it has a larger OT. Leo would have fitted a larger cap if he could but 32uF is the max when used with a 5Y3 rectifier. Check out the AX84 P1 or the VJ V3 for a well designed power supply.

Yeah, here's my 5F2A clone ...

http://img.photobucket.com/albums/v82/rfdee/frettech/5f2a.jpg

... a bit louder, more headroom, overall sweeter tone than my 5F1's and GA-5.

So, 30/10/10 might be good filter cap values to check out with the GA-5. How 'bout running a pair of 16's in parallel for 32/10/10?

There are other issues with the BC Mini IMO but those cap values don't make any sense.

All I know is that BC Mini had the worst tube amp tone I'd ever heard. I was thinking there HAD to be something wrong with that amp ...



....

Anyone want my GA-5 before I send it back? I've got a Fender Super champ XD on the way which is more to my taste. I did the first mod, but can solder it back (which I will have to anyhow before I send it back) or leave as is, your choice.

I've had it for about three weeks. Let me know. $300 + actual shipping charges from 78414 via FedEx for UPS. Money order or Paypal (3% fee for Paypal).

PMed.

....
Yes, you could parallel a 20uF or bigger with the first cap. Making the second a 20uF would also help.

Yes, you could parallel a 20uF or bigger with the first cap. Making the second a 20uF would also help.

Summa this filter cap talk is starting to smell of snake oil, or at best it's all about personal tastes and that will involve lots 'n' lots of 'sperimentin'.

I'm gonna taste test 20/10/10 and maybe 32/10/10, and unless I can actually hear viable sonic differences I'm gonna call "bogus" on all this filter cap krap. It's beginning to sound like a buncha "maple fingerboards are brighter than rosewood" kinda BS. I'll see. The only real positive cap differences I actually heard for the better were replacing the Mallory couplers with Jupiters.

Summa this filter cap talk is starting to smell of snake oil, or at best it's all about personal tastes and that will involve lots 'n' lots of 'sperimentin'.

I'm gonna taste test 20/10/10 and maybe 32/10/10, and unless I can actually hear viable sonic differences I'm gonna call "bogus" on all this filter cap krap. It's beginning to sound like a buncha "maple fingerboards are brighter than rosewood" kinda BS. I'll see. The only real positive cap differences I actually heard for the better were replacing the Mallory couplers with Jupiters.

Like I said, I've run my 5E3 clone with a 30uF first filter cap and two 16uF filter caps (30/16/16) and also thre 16uF filter caps (16/16/16).

The difference, not in tone, but in how the amp broke up and the texture of the breakup, was pretty dramatic. The 30uF makes the amp tighter. Using the 16uF first filter cap and a guitar with humbukers that amp sounded loose, almost like it was going falling apart.

I didn't hear any "difference in tone" at all.

I also used two 16uF caps in parallel before using a 30uF with the same results. I switched to the 30uF cap just to neaten up the circuit.

BTW, my goal is to loosen my GA-5 up a bit.

I had read, several years ago, that circuits like these did not sound as good over filtered.

That's been my experience as well.

It may sound a good idea to go wild with filtering, but it can have a negative effect on the amps dynamics and response, making its character one dimensional and kind of flat as a board.

Getting carried away on the preamp filtering can seriously make the amp sound sterile, with less dynamics.

Keep in mind this is a 5 watt amplifier. I'm reading some filtering values that would no doubt be way over the top in a 20 watt amp.

Nothing wrong with beefing the filtering so the amp holds together better at higher volumes, but it's best to go at it moderately.

But, to each his own.

Warning: don't go installing these wild amounts of filtering on your amps with tube rectifiers. Tube rectifiers have their limits on the amount of current they can produce, and all that capacitance charging up when the amp is turned on can blow your tube rectifier.

Darn - I checked Musicians Friend like I do every few hours and they had a blem for $260. When I hit "order" they responded it was already sold... oh well, keep on truckin'!

M123 has cancelled all pending GA-5 orders and no longer offers it on their site.

M123 has cancelled all pending GA-5 orders and no longer offers it on their site.

Guess I need to call them - they ain't notified me!

I linked to the page directly for the amp and it usually says "discontinued", etc, but when they get a return it must go out as a Scratch & Dent. If you go to the page they still have one listed for sale, but when you click Buy it - it says it's already sold. I'm hoping at some point my timing will be better...
:sad:

Guess I need to call them - they ain't notified me!

Wasn't notified, just checked my online order invoice and it was canceled.

Here's some GA-5 sound bytes I hastily created by plugging in a partscaster Strat into the modded GA-5 as recorded with a Zoom H2 positioned about a foot away from the speaker cone. No FX. The stereo recording was trimmed (not edited) with my old Cool Edit 2K software.

One take on each, so excuse the mistakes - used the Lawrence L200 noiseless neck pup (the other pups are Lawrence Keystone true single coils), 11-48 DaddyO's, fingers only/no pick, volume full on, no-load tone pot engaged (no cap in the circuit, 2nd tone pot is actually a neck vol blender).

The GA-5's volume is set at noon - you can hear some breakup happening as based on picking hand attack.

The tunes are mellow, no rock 'n' roll or blues, so you can get a feel for the amp's tone comin' outta the 8F150. Besides the speaker swap, this GA-5 has the 25uf cap removed, hi-pass cap/resistor removed, no NFB resistor, Jupiter Vintage Tone coupling caps, Atom filter caps 22/16/16, 1.5k resistor between the preamp pin 7 and the shielded signal lead off the vol pot.

IMO, the 8F150 is just too bottom end heavy and I'd need to tweak the caps to tighten that up - but I'll wait to tray out the 8A125T that's due to arrive next Wednesday.

I'll look to put some raunchy rock/blues sounds together later, played with and without a pick.

Ragtime, 8 meg WAV file (http://216.147.79.19/wav/ga5b.wav)

Jazz, 18 meg WAV file (http://216.147.79.19/wav/ga5d.wav)

http://img.photobucket.com/albums/v82/rfdee/frettech/strat.jpg

Nice. Thanks for posting those up! There is a lot of bottom end going on there, I'll be looking forward to hearing more, and also from the stock GA5!

droo


edited to add....the more I listen, the more I hear that bottom end. HArd to believe it's an 8!

Rob very nice playing there :cool: I think I like the fullness of the Weber 8150t I just might have to buy one for my Mini Z or see if I can inlarge the baffle hole to 10" and try this weber speaker British ceramic V10

https://taweber.powweb.com/weber/c10v.mp3

... or see if I can inlarge the baffle hole to 10" and try this weber speaker British ceramic V10



Earlier in this thread I checked out if the cab/chassis would accept a 10" speaker - it won't fit unless you mod either, or both, the speaker basket and chassis frame.

http://www.tdpri.com/forum/amp-central-station/99134-%24299-gibson-tube-amp-made-usa-5.html#post1141378

I wouldn't be surprised if the same people who made the GA-5 also made the DrZ. Did Mojo build these?


A Gibson customer service rep told me that the GA-5s were built in North Carolina. Mojo is in North Carolina and the amps have quite a few Mojo parts in them. I assume Mojo built them.

Anybody find a longer cord for the GA-5?

Eight feet would be nice. Ten would be better than what is stock.

Anybody find a longer cord for the GA-5?

Eight feet would be nice. Ten would be better than what is stock.

I've got a 12' installed in mine. It's almost silly on such a small amp, but what the hey, I had it in a box of cords...

Any power chord that has that "computer-like power cord" end on it will work.

I *believe* the S-W124 @ Antique Electronics (http://www.tubesandmore.com/) is what you need

I've got a 12' installed in mine. It's almost silly on such a small amp, but what the hey, I had it in a box of cords...

Any power chord that has that "computer-like power cord" end on it will work.

I *believe* the S-W124 @ Antique Electronics (http://www.tubesandmore.com/) is what you need



Thanks - I'll try the 123 -

8 feet instead of the 12 foot 124.

Like most modern amps, the GA-5 sports an IEC power socket - any computer power supply power cord will work, and they come in at least lengths of 4' to 15'.

He shoots! He scores!!! :mrgreen:

maybe. I checked MF this morning and they said there was a blem for $260. I hit the buy button and the sale seems to have gone through. I also got an e-mail verification that my sale was good. I hope that's true!!!

Sometimes, persistence pays off!


now I'll have to go back and really read up on all the mods to make this thing sing!

i used ga5 last night at a gig, people were getting a kick on how small it was!

i used ga5 last night at a gig, people were getting a kick on how small it was!


What are the details? Mic'ed? Small house? Type of tunes?

droo

What are the details? Mic'ed? Small house? Type of tunes?

droo

In a nice size bar/burger joint in downtown baton rouge. Not mic'ed, daisy chained with a lil dawg champ.

Rosie Ledet. It's zydeco music.

Eh twa!

In a nice size bar/burger joint in downtown baton rouge. Not mic'ed, daisy chained with a lil dawg champ.

Rosie Ledet. It's zydeco music.

Eh twa!

Right on! Lil' Dawg and a GA-5, nice. I'm gigging mine tonight too...medium sized, mic'ed through the PA. It's been working like a charm. Just enough stage volume.

Voodoo BBQ...we're zydeco/funk from the Northwest :)

droo

In a nice size bar/burger joint in downtown baton rouge. Not mic'ed, daisy chained with a lil dawg champ.

Rosie Ledet. It's zydeco music.

Eh twa!

Sorry i have to make correction...i'm a lil burnt :lol:

After a few songs, they sound guy mic'ed my lil dawg champ but not the GA5.

I had no monitor for guitar, but the two amps on stage we plenty!

All the tone enhancing mods posted here are very interesting (and nicely documented) and I look forward to trying them (so I can finally put my EE degree to some use). I want to take some time playing the stock circuit with the 8F150 i've got on order before doing much tinkering. That said, I am interested in doing a few things to make the amp as noiseless and free of hums & buzzes as possible. Here's a list of what I've found on this thread so far:

1. Add tube shield to the 12AX7 preamp tube.

2. The thing that made the most difference in noise was shielding the top and edges of the cabinet with heavy duty aluminum foil. Amps spray a lot of noise, that tends to wreak havoc with single coils. Shielding the cab completely seals the electronics electrically, which reduces that crap quit a bit. I use Reynolds heavy duty aluminum foil, spray on some 3M spray adhesive cement, fit to the cab top - in the case of the GA-5, the foil should run down the sides and into the chassis slot to complete the ground. Alum foil makes for a good noise shield.

3. Shield the signal lead off the vol pot to pin 7 of the preamp tube socket.

4. Break the ground buss between the preamp and power sections.

Does anyone have any other suggestions to minimize hum, buzz, and background noise?

All the tone enhancing mods posted here are very interesting (and nicely documented) and I look forward to trying them (so I can finally put my EE degree to some use). I want to take some time playing the stock circuit with the 8F150 i've got on order before doing much tinkering. That said, I am interested in doing a few things to make the amp as noiseless and free of hums & buzzes as possible. Here's a list of what I've found on this thread so far:

1. Add tube shield to the 12AX7 preamp tube.

2. The thing that made the most difference in noise was shielding the top and edges of the cabinet with heavy duty aluminum foil. Amps spray a lot of noise, that tends to wreak havoc with single coils. Shielding the cab completely seals the electronics electrically, which reduces that crap quit a bit. I use Reynolds heavy duty aluminum foil, spray on some 3M spray adhesive cement, fit to the cab top - in the case of the GA-5, the foil should run down the sides and into the chassis slot to complete the ground. Alum foil makes for a good noise shield.

3. Shield the signal lead off the vol pot to pin 7 of the preamp tube socket.

4. Break the ground buss between the preamp and power sections.

Does anyone have any other suggestions to minimize hum, buzz, and background noise?

Make sure if you break the ground buss, that the new "preamp buss" is grounded to the chassis in some way. I recommend installing common Switchcraft 1/4" jacks, and this will take care of it. However you arrange it, as long as the buss is connected to the ground on the 1/4" jacks, that makes the connection to the chassis.

Single ended amps are bad about hum. Another thing that one can do that will have a big impact, is to convert the filament supply to DC. Gee posted his Baby Vox Mod schematic for the VJ on this thread a ways back, that shows this. I don't believe filtering as high as 4700uF is necessary. I would think that 200uF would be more than enough, but I'm not experienced with DC filament supplies...

http://www.tdpri.com/forum/attachments/amp-central-station/10085d1206633553-%24299-gibson-tube-amp-made-usa-baby_voxy-pdf

Thanks for the reply "Specialty Guitars".

FYI, I was poking around for a more "industrial strengh" shielding foil and found 3M makes several.

The one I found particularly interesting due to the "form factor" can be seen here:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=3M1115D-1FT-ND

I think a few pieces of this would do the trick!

Tape Type: EMI Shielding
Adhesive: Acrylic, Conductive
Backing, Carrier: Aluminum Foil
Size: 6.00" W x 1.0' L (152.4mm x 304.8mm)
Thickness: 0.007" (7.0 mils, 0.178mm)
Usage: Shielding, Grounding

Alternatively, I'm wondering how the smooth, relatively thick base of a disposable aluminum baking pan would do as compared to thinner "reynolds wrap" product.

Note MOUSER has some good options for 3M Self Adhesive EMI/RFI Shielding Sheets in convenient sizes:

http://www.mouser.com/catalog/631/1906.pdf

Thanks for the reply "Specialty Guitars".

FYI, I was poking around for a more "industrial strengh" shielding foil and found 3M makes several.

The one I found particularly interesting due to the "form factor" can be seen here:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=3M1115D-1FT-ND

I think a few pieces of this would do the trick!

Tape Type: EMI Shielding
Adhesive: Acrylic, Conductive
Backing, Carrier: Aluminum Foil
Size: 6.00" W x 1.0' L (152.4mm x 304.8mm)
Thickness: 0.007" (7.0 mils, 0.178mm)
Usage: Shielding, Grounding

Alternatively, I'm wondering how the smooth, relatively thick base of a disposable aluminum baking pan would do as compared to thinner "reynolds wrap" product.

Hey Sevan, you're really on it! Excellent.

I'm not sure that thicker shielding is really better, but I just don't know. I believe that whatever is easiest to work with (some amps use screen instead of solid foil) is the way to go.

If you've ever seen guys who work on sensitive RF equipment, they work in "cages" or "screen rooms" to block any RF and other crap from getting to the equipment they're working on. As long as the metal mesh or screen enclosing the equipment is tight enough to block the wave lengths of the frequencies desired, that's good enough. In an amp, 60 and 120 hz are the big issues, and these are large wave lengths, so even window screen mesh should work as well as any foil.

So I don't believe that thicker foil would be better, but I'm not 100% certain.

I have used self adhesive foil tape for heating duct work that does the trick nicely. You can find rolls of it at Home Depot for a good price. Easy to work with.

I have used self adhesive foil tape for heating duct work that does the trick nicely. You can find rolls of it at Home Depot for a good price. Easy to work with.

I've got a ton of that stuff in my basement - great idea!

I find the HD Reynolds does the trick with a few smears of contact or even rubber cement. Effective. Easy. Cheap.

Has anyone had problems with a cabinet or speaker buzz? It's especially noticeable on the E and A strings and neck pickup, even at low volumes. Haven't been able to find it so far which makes me think it could be the speaker. Thanks for any suggestions!

Has anyone had problems with a cabinet or speaker buzz? It's especially noticeable on the E and A strings and neck pickup, even at low volumes. Haven't been able to find it so far which makes me think it could be the speaker. Thanks for any suggestions!

I have, big time - and it turned out to be parasitics from some instability in the circuit. The remedy is a 1.5k resistor between the preamp socket pin 7 and the signal lead that comes off the volume pot.

...In an amp, 60 and 120 hz are the big issues, and these are large wave lengths, so even window screen mesh should work as well as any foil. ...


On older Fenders, I've seen alum screen mesh stapled to the underside of cab tops, sandwiched between the open chassis bottom and the cab top.

On older Fenders, I've seen alum screen mesh stapled to the underside of cab tops, sandwiched between the open chassis bottom and the cab top.

Exactly.

I have, big time - and it turned out to be parasitics from some instability in the circuit. The remedy is a 1.5k resistor between the preamp socket pin 7 and the signal lead that comes off the volume pot.

Yep, parasitic oscillations can manifest themselves in all sorts of ways. The ones that sound like a blown speaker, or blown output transformer can send you down an expensive and frustrating long and winding wrong road...

Thanks Rob!

Thanks Rob!

No no no - thanx to Paul!

Some good info about parasitics and how to diagnose & cure them can be found here (from pg 61 onward):

http://books.google.com/books?id=lG8361HKf6kC&pg=PA61&lpg=PA61&dq=tube+amp+parasitic+oscillations+&source=web&ots=2gNrCQtXd7&sig=UIqRGORw2wC1xRlEcna6qV_-mxI&hl=en#PPA63,M1

I have an old vintage Jensen alnico speaker - an 8J11 - from a Harmony H400 amp -

(having owned a couple of the H400's I can tell you w/o fear of contradiction that the Jensen speakers are the best part of those amps) -

anyway, stuck it in my GA-5 - stock except for removal of the wire meshes and wood cord box -

and I like the sound of it very much!

Based on a quick test run I find the Jensen less efficient and the sound of the amp fuller and more articulate at a lower volume - does that make sense? The break is just as sweet - again, though, at what I perceive to be a lower volume than the stock Goldtone/Weber. With the Weber it seemed I would kinda hunt for a sweet spot in the guitar/amp volume settings. The Jensen sounds "better" throughout the dial.

Admittedly, the Weber is not broken in - the Jensen is 40 plus years old!

A few years ago when I had my first flirt with cheap Harmony amps I learned that the 8J11 was stock on some vintage Gibson amps - maybe something to do with it?

Anyway, I'll leave it in for now.

Mine arrived last night.
I have been playing the past couple years through a solid state with a 12 inch speaker, so my first reaction was "oh!" :shock:

Quite a difference! I had forgotten what tubes felt like!

After, I tried the gain channel on the solid state and realised how nasty it sounds.

I will say though that I prefer the Kustom 12 Gauge clean sound , because of the 12 inch speaker, and it also has a sparkle. But with the volume down on the guitar , you can get almost the sound.
In fact, if you have a guitar with a volume and tone knob, and a good reverb pedal... (or whatever other effects you enjoy) , then I think you can use this amp in a number of versatile ways.

I really like this amp.

As is , with no mods at all, i'm quite satisfied.

Some advice, if I may,... if you live in a close quaters apt. building with paper-thin walls... think twice before buying this amp! It wants to be turned up, and it is stinkin LOUD!
I'm having issues with this already.

I have an old vintage Jensen alnico speaker - an 8J11 - from a Harmony H400 amp -

(having owned a couple of the H400's I can tell you w/o fear of contradiction that the Jensen speakers are the best part of those amps) -

anyway, stuck it in my GA-5 - stock except for removal of the wire meshes and wood cord box -

and I like the sound of it very much!

Based on a quick test run I find the Jensen less efficient and the sound of the amp fuller and more articulate at a lower volume - does that make sense? The break is just as sweet - again, though, at what I perceive to be a lower volume than the stock Goldtone/Weber. With the Weber it seemed I would kinda hunt for a sweet spot in the guitar/amp volume settings. The Jensen sounds "better" throughout the dial.

Admittedly, the Weber is not broken in - the Jensen is 40 plus years old!

A few years ago when I had my first flirt with cheap Harmony amps I learned that the 8J11 was stock on some vintage Gibson amps - maybe something to do with it?

Anyway, I'll leave it in for now.

Is your Jensen 4 or 8 ohms? If it's 8 ohms, it will sound better and be more efficient if you switch the 8 ohm tap of the output transformer to the speaker jack.

I don't know what was typically used in Harmonys, but It looks like vintage Gibsons typically used 8 ohm 8"s.

No no no - thanx to Paul!

LOL...no worries Rob. I don't mind being the "ghost" modder. :wink:

Is your Jensen 4 or 8 ohms? If it's 8 ohms, it will sound better and be more efficient if you switch the 8 ohm tap of the output transformer to the speaker jack.

I don't know what was typically used in Harmonys, but It looks like vintage Gibsons typically used 8 ohm 8"s.

Its a 4 ohm.

Some quickee sound bytes comparing a box-stock GA-5, then modding that same GA-5 with only the trinity mods. Vol set at noon.

Quite diff'rent tones - the stock amp has that raw, raunchy, louder energy whereas the modded amp is more laid back, mellowed and lower volume. Lifting the NFB adds back a good measure of that rock 'n' roll tone (as I've done with my modded GA-5).

Same Strat as before, mic'd with a Zoom H2 in stereo at about 12" off the Sig 8 speaker cone. The first rock licks are picked using the Keystone bridge pickup, the second ragtime tune is fingerpicked using the neck L200 noiseless pickup.

6 meg WAV file ...
Stock GA-5 (http://216.147.79.19/wav/ga5-stock.wav)

6.7 meg WAV file ...
Trinity GA-5 (http://216.147.79.19/wav/ga5-trinity.wav)

Its a 4 ohm.

Right on.

Has anyone tried a Weber ceramic Blue Pup 8" in one of these yet? I'm curious if the magnet is too large, and will touch the EL84 or its retainer.

Some quickee sound bytes comparing a box-stock GA-5, then modding that same GA-5 with only the trinity mods.

Quite diff'rent tones - the stock amp has that raw, raunchy, louder energy whereas the modded amp is more laid back and mellowed. Lifting the NFB adds back a good measure of that rock 'n' roll tone (as I've done with my modded GA-5).

Same Strat as before, mic'd with a Zoom H2 in stereo at about 12" off the Sig 8 speaker cone. The first rock licks are picked using the Keystone bridge pickup, the second ragtime tune is fingerpicked using the neck L200 noiseless pickup.

6 meg WAV file ...
Stock GA-5 (http://216.147.79.19/wav/ga5-stock.wav)

6.7 meg WAV file ...
Trinity GA-5 (http://216.147.79.19/wav/ga5-trinity.wav)


Rob,

Tasty playing!

Your clips play muddy for for me. Is this something on my end, or the way the clips are recorded?

...Your clips play muddy for for me. Is this something on my end, or the way the clips are recorded?

Hmmm, don't hear that on my end. They're crisp WAV files, and there is is some goodly breakup happening (with the amp pushed halfway), particularly on the plectrum stuff, and very little on the fingerpicked stuff. Dunno ...

Has anyone tried a Weber ceramic Blue Pup 8" in one of these yet? I'm curious if the magnet is too large, and will touch the EL84 or its retainer.

Good question. The 8F150 has the largest mag ring of any Weber 8" and the EL84's spring retainer hits it a bit - bending or removing the retainer would allow that speaker to fit. I think the Blue Pup's mag ring is a tad smaller ... ?

Heck - did a little Googling -

and it seems the 8J11 was stock in the Gibson Skylark - you know,

the original GA-5! :cool:

(scroll down and you'll find it - and find a lot of other cool Gibson amp info along the way)

http://www.harmonicamasterclass.com/vintage_amps.htm

For guys like me who haven't used in years, and are not interested in using a soldering iron anymore, I recommend a eq pedal.
I've also experimented with my Digitech RP 150 and it sounds terrific.
With an eq you can make it sound great! no muss - no fuss!

...With an eq you can make it sound great! no muss - no fuss!

IMHO, close but no cigar when compared to having the amp itself sound Great sans any modulation interfaces - and that "close" might just be good enuf for some folks, cool. YMMV.

yea Rob, I know what you mean, but I have 6 thumbs. It is interesting to read what you have done , and it sounds great. Great work!
As for me, i'll have to make the best of it here, but it does sound quite good... i'm happy!

... As for me, i'll have to make the best of it here, but it does sound quite good... i'm happy!

Cool! :cool:

Nice playing in those clips Rob.
I think cutting back on the negative feedback by about half would be just perfect...anyone know what value resistor that would be?

My "vintage" Sozo caps showed up today so I stuck them in the amp and let them burn in a couple of hours. Compared to the Mallory 150s the amps sounds a little more clear in the mids and more "eager" if that makes sense. Notes seem to jump out of the amp. Well worth the few bucks.

Hmmm, don't hear that on my end. They're crisp WAV files, and there is is some goodly breakup happening (with the amp pushed halfway), particularly on the plectrum stuff, and very little on the fingerpicked stuff. Dunno ...

I can tell the difference between distorted guitar and distorted playback. I have thought for some time that the WMP on this computer had trouble with certain files, but was never sure.

If the clips sound correct to you and everyone else, it must be this computer's WMP.

..I think cutting back on the negative feedback by about half would be just perfect...anyone know what value resistor that would be?. ...

I took the NFB outta my GA-5, it works better for me because the 8F150 speaker is so dark and heavy.

Why not replace the NFB resistor with trim pot, say 100K, 200K? Then dial in what sounds best?

I think cutting back on the negative feedback by about half would be just perfect...anyone know what value resistor that would be?

If you want half the amount of NFB, you'll have to experiment with higher value resistors. If you have a 47k in it now, which is is the mod that I prescribed, that is the same value the vintage GA5 had, try a 100K and see what you think. Then work your way up or down in resistor value from there. The higher the resistor value, the less NFB.

I took the NFB outta my GA-5, it works better for me because the 8F150 speaker is so dark and heavy.

Rob, how does that speaker sound when you wind the amp up?

Rob, how does that speaker sound when you wind the amp up?

Not good at all - WAY too much bottom end. The 8F150 might be best in the stock GA-5, not in the modded one without the NFB and with the 1st two trinity mods accomplished. I think the perfect "standard" speaker for this amp might just the AlNiCo Blue Pup or the CVA8.

I just listened to both clips about 10 times each and I think I prefer the stock sound.

The modded amp sounds like its being played while sealed inside a cardboard box.

I think the perfect "standard" speaker for this amp might just the AlNiCo Blue Pup or the CVA8.

Yeah, that's what I was thinking. The 8F150 and such have large voice coils and huge magnets that are going to give some serious low end rumble. The vintage designs that this amp is based on were designed around the Jensens they had access to in the day, and it all worked out fairly well. I think when you get too far from the vintage "recipe" you risk upsetting the balance.

Now with mine, after doing the mods, I went to that Kendrick 8", which is similar to the CV8 and Sig series. Like you, after I added the 47k NFB resistor (which I can't live without, and love the way it tames the rawness) my amp had strong bass (though that speaker has a relatively small ceramic magnet) and lost a good bit of brightness when turned down low. This is a common problem, and is why I installed the 22pF as a treble bypass on the volume control, which evened everything out very nicely.

I have since moved to a 47pF silver mica on the volume pot, and the amp sounds beautiful. Nice glassy, chimie cleans with good clear low end, wicked when cranked, and with a touch of attitude in between.

I found the rawness with no NFB to be intriguing, but not terribly useful, and kind of fatiguing on the ears.

But that's the cool thing, we all have different playing styles, ears, guitars etc. and almost everyone can tweak this amp to their liking, one way or another.

I just listened to both clips about 10 times each and I think I prefer the stock sound.

The modded amp sounds like its being played while sealed inside a cardboard box.

I trinity modded (and also did the Carling switch swap) that particular amp for a gigging acoustic guitarist, and those mods fit his acoustic guitars and playing style just fine, whereas in the box stock tweed city state it was nearly useless. Like what Paul (and I) have been saying - if need be, mod the amp to your playing tastes.

Try the first 2 trinity mods, and leave out the NFB - that adds a healthy dose of rock 'n' roll tone and loses the gritty boxiness.

BTW, a Taylor 655 12 string sounds *glorious* through a trinity modded GA-5! :cool:

Yeah, that's what I was thinking. The 8F150 and such have large voice coils and huge magnets that are going to give some serious low end rumble. The vintage designs that this amp is based on were designed around the Jensens they had access to in the day, and it all worked out fairly well. I think when you get too far from the vintage "recipe" you risk upsetting the balance.

Now with mine, after doing the mods, I went to that Kendrick 8", which is similar to the CV8 and Sig series. Like you, after I added the 47k NFB resistor (which I can't live without, and love the way it tames the rawness) my amp had strong bass (though that speaker has a relatively small ceramic magnet) and lost a good bit of brightness when turned down low. This is a common problem, and is why I installed the 22pF as a treble bypass on the volume control, which evened everything out very nicely.

I have since moved to a 47pF silver mica on the volume pot, and the amp sounds beautiful. Nice glassy, chimie cleans with good clear low end, wicked when cranked, and with a touch of attitude in between.

I found the rawness with no NFB to be intriguing, but not terribly useful, and kind of fatiguing on the ears.

But that's the cool thing, we all have different playing styles, ears, guitars etc. and almost everyone can tweak this amp to their liking, one way or another.

I think that part of this speaker thing is that new ones are gonna take some time to "break in" ... in fact, even the components are probably gonna go through some "forming" cycle as well. Add up all the little differences between all of our GA-5's and and how and what music we individually play and, well, it all becomes an "experiment of one" as the good Dr. Sheehan would muse. :cool:

Yeah, that's what I was thinking. The 8F150 and such have large voice coils and huge magnets that are going to give some serious low end rumble. The vintage designs that this amp is based on were designed around the Jensens they had access to in the day, and it all worked out fairly well. I think when you get too far from the vintage "recipe" you risk upsetting the balance.

Now with mine, after doing the mods, I went to that Kendrick 8", which is similar to the CV8 and Sig series. Like you, after I added the 47k NFB resistor (which I can't live without, and love the way it tames the rawness) my amp had strong bass (though that speaker has a relatively small ceramic magnet) and lost a good bit of brightness when turned down low. This is a common problem, and is why I installed the 22pF as a treble bypass on the volume control, which evened everything out very nicely.

I have since moved to a 47pF silver mica on the volume pot, and the amp sounds beautiful. Nice glassy, chimie cleans with good clear low end, wicked when cranked, and with a touch of attitude in between.

I found the rawness with no NFB to be intriguing, but not terribly useful, and kind of fatiguing on the ears.

But that's the cool thing, we all have different playing styles, ears, guitars etc. and almost everyone can tweak this amp to their liking, one way or another.


See my post above - the original GA-5 came with a small-magnet alnico Jensen FWIW. Don't know nothin about nothin and my ears are made of wood but I like what that amp sounds like even more now.

Other than stripping out the grills and stupid box - and the addition of a longer power cord - I plan on doing nothing more to mine than the speaker change. Having that old Jensen in it "softened" the GA-5 in a good way to my ears.

Messing around with the amp today swapping in the speaker re-affirmed my initial impression of the amp - it is a very solidly made unit - built to last. As you modders have demonstrated, it is also a breeze to work on.

I think that part of this speaker thing is that new ones are gonna take some time to "break in" ... in fact, even the components are probably gonna go through some "forming" cycle as well. Add up all the little differences between all of our GA-5's and and how and what music we individually play and, well, it all becomes an "experiment of one" as the good Dr. Sheehan would muse. :cool:

Sure the break-in periods come into play, but I can usually break in a new Weber speaker, with a couple of serious 10 minute or so "floggings" with the amp cranked, (and in a closet to save my ears). And the Jupiter Vintage Tone caps only need several hours to break in.

Based on my experience, after I did the mods, and installed the Kendrick speaker, and heard the bass response this little amp had, I was concerned that those of you who ordered the serious big magnet 8" "battleships" from Weber, might have a challenge on your hands.

Again, all this amp stuff is a complex balancing act. It's kind of like multi-dimensional surfing.

Rob, based on the music you played in your clips, I don't see how you could live without the NFB mod. I play similar jazzy blues (or is it bluesy jazz?) rockabilly, etc.

I seriously need to figure out how to record some clips. I believe you would enjoy hearing my GA5. It is nice and clean then breaks up smoothly.

To my ears, the "box stock" GA5 sounded kind of Voxy and rock, and the modded GA5 sounds like a lively, chimie tweed.

These mods make the new GA5 more like the vintage GA5

1. Removal of the high-pass filter. This adds back the "balls" that the filter removed.
2. Adding the 47k NFB resistor. This smooths and evens out the frequency response, or puts the "balls" from #1 in briefs, if you will.

This mod made it more like a 5F1 Champ

3. Removal of the 1st stage cathode bypass capacitor, which to my ears gets rid of that "crispy" gain that the stock GA5 Ris have. (the vintage GA5 and vintage Fender 5E1 had this installed)

This mod is a "generic" mod to brighten the amp when the volume is turned down low

4. Installing the 22pF cap that was removed in mod #1 on the volume control as a treble bypass. Which compensates for the loss of high end when installing mod #2. A 47pF, 100pF etc. can also be used, and silver mica caps sound smoother than ceramic disks. Neither one is necessarily better than the other, they are just different.

Of course I must add that wonderful, generic disclaimer... YMMV

I just listened to both clips about 10 times each and I think I prefer the stock sound.+1 :cool:

I would like to hear both amps with better speakers

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To quote Inspector Clouseau "Not anymore..."

4. Installing the 22pF cap that was removed in mod #1 on the volume control as a treble bypass. Which compensates for the loss of high end when installing mod #2. A 47pF, 100pF etc. can also be used, and silver mica caps sound smoother than ceramic disks. Neither one is necessarily better than the other, they are just different.

I just tried the 22pF cap on the volume control and LOVE it! It might be my favorite single mod. I'd like to try 47pF and 100pF, silver mica as well.

I installed a 16uF and two 10uF Sprague Atoms in the amp earlier today. It loosened up the amp a bit. It has a more old fashioned feel. The amp did not respond to the change in filter cap values as much as my 5E3 clone did, but the amps are quite different.

I just tried the 22pF cap on the volume control and LOVE it! It might be my favorite single mod. I'd like to try 47pF and 100pF, silver mica as well.

I installed a 16uF and two 10uF Sprague Atoms in the amp earlier today. It loosened up the amp a bit. It has a more old fashioned feel. The amp did not respond to the change in filter cap values as much as my 5E3 clone did, but the amps are quite different.

Don,

I've been fooling with different filter cap brands and values in this amp, and my 1951 GA20. I have found that a 10uF in the middle (screen filter) sounds flat. If you have one, please try a 16uF Sprague Atom in that position along with what you have, or 20/20/10 (all Sprague Atoms) and let me know what you think.

I'm trying to zero in on the best setup, not for the modern, stiff "Vox clone" sound, but for the best full, clear chime and bass with touch response.

I just tried the 22pF cap on the volume control and LOVE it! It might be my favorite single mod. I'd like to try 47pF and 100pF, silver mica as well.

PS. The tweed bright channels use 100pF and IMHO that is not the best. IMHO stick with 22pF and 47pF in both silver mica and ceramic to see what's best for you in your GA5.

I just tried the 22pF cap on the volume control and LOVE it! It might be my favorite single mod.

The way I've been using mine is with the volume all the way up. I control the volume with the guitar. So the treble bypass mod wouldn't do anything for me.

When the amp was stock, I had to turn down the volume on the amp to get it in a usable range. That forces the signal to go through the amp's volume knob, but after I calmed the amp down with the "trinity" mods, I am able to get the sounds I'm after with the amp all the way up. I just roll my strat volume back for clean, and I get all the dirt I need when the guitar volume is up. I haven't been using any pedals at all.

One other thing, while I've been using my amp with the volume all the way up, I still do not have any noise problems with the amp. It is quiet as can be. I don't think they all need shielding. The only hum I get is when I'm using single coil pups near a refrigerator, computer or fluorescent light.

You might try a line conditioner with a voltage regulator and a surge protector to clean up that hum.

After, I tried the gain channel on the solid state and realised how nasty it sounds.


Brother, I hear you. I have a Bandit II I haven't been using much lately. I tried it for the first time since getting the GA-5. This Bandit II is going to my brother in law as soon as possible, peeewwww.

Rob, nice clips! I liked both sounds... could a guy toss a switch in so he could go back and forth?

Rob, nice clips! I liked both sounds... could a guy toss a switch in so he could go back and forth?

Unfortunately...

To my ears, the "box stock" GA5 sounded kind of Voxy and rock, and the modded GA5 sounds like a lively, chimie tweed.

These mods make the new GA5 more like the vintage GA5

1. Removal of the high-pass filter. This adds back the "balls" that the filter removed.
2. Adding the 47k NFB resistor. This smooths and evens out the frequency response, or puts the "balls" from #1 in briefs, if you will.

This mod made it more like a 5F1 Champ

3. Removal of the 1st stage cathode bypass capacitor, which to my ears gets rid of that "crispy" gain that the stock GA5 Ris have. (the vintage GA5 and vintage Fender 5E1 had this installed)

This mod is a "generic" mod to brighten the amp when the volume is turned down low

4. Installing the 22pF cap that was removed in mod #1 on the volume control as a treble bypass. Which compensates for the loss of high end when installing mod #2. A 47pF, 100pF etc. can also be used, and silver mica caps sound smoother than ceramic disks. Neither one is necessarily better than the other, they are just different.

Of course I must add that wonderful, generic disclaimer... YMMV

...it's not quite a simple toss of a switch kind of thing.

Don,

I've been fooling with different filter cap brands and values in this amp, and my 1951 GA20. I have found that a 10uF in the middle (screen filter) sounds flat. If you have one, please try a 16uF Sprague Atom in that position along with what you have, or 20/20/10 (all Sprague Atoms) and let me know what you think.

I'm trying to zero in on the best setup, not for the modern, stiff "Vox clone" sound, but for the best full, clear chime and bass with touch response.

Would you suggest using the Beeswax caps or the JVT's? Thank you.
Will the 30 in the 1st position tighten the lows and 10's in the 2nd and third allow full spectrum mids and highs thru? (using this on a stock GA-5). thanks.

Rob, nice clips! I liked both sounds... could a guy toss a switch in so he could go back and forth?

A very difficult feat with a single switch - multiple switches required at least and that won't be easy, either. You could also use DPDT switches to completely remove components, locate the switches close to the components in question, and shield all leads.

IMO, after thinking too long and hard about switching some or all of the trinity mods, I'd rather spend the extra time and dial the amp in for my needs and tastes. This will mean tweaking all modulation mods, cap values and speakers to suit my guitars and playing style. The obligatory YMMV goes here. :cool:

... Rob, based on the music you played in your clips, I don't see how you could live without the NFB mod. I play similar jazzy blues (or is it bluesy jazz?) rockabilly, etc. ...

With my GA5, the NFB just adds way too much to an already over saturated bottom end. I need to better tweak the filter caps and speaker, first. The NFB is the only mod I'd consider assigning to a DPDT switch.

One other thing, while I've been using my amp with the volume all the way up, I still do not have any noise problems with the amp. It is quiet as can be. I don't think they all need shielding. The only hum I get is when I'm using single coil pups near a refrigerator, computer or fluorescent light.

Mine is quiet too.

The way I've been using mine is with the volume all the way up. I control the volume with the guitar. So the treble bypass mod wouldn't do anything for me.

My GA-5 doesn't clean up like my 5E3 clone does. The guitar gets dark as I roll it's volume back. This is not the case when I doe the same thing with my 5E3.

My GA-5 doesn't clean up like my 5E3 clone does. The guitar gets dark as I roll it's volume back. This is not the case when I doe the same thing with my 5E3.

If your amp is set up for more gain (cathode cap stock, no NFB), you've got to roll volumes back much more to clean it up, which could lead to a darker sounding clean. Since I added the NFB, clipped out the cathode cap & removed the fixed tone stack, the amp is much cleaner at max volume than stock.

When you switch the amp to have all three trinity mods switched on, plug into input #2, and crank the amp volume to max, does it behaves better to the guitar volume without darkening up?

It is kind of interesting that everyone is having such different experiences with these amps. I wonder if it is just each person's style & perceptions or if there is a decent amount of variation in these amps.

They are dark sounding to some, but to others its the brightest amp they own.

Mine plays real nice with the guitar volume knob, while others don't have that same experience. It was very dark before the mods though.

With my GA5, the NFB just adds way too much to an already over saturated bottom end. I need to better tweak the filter caps and speaker, first. The NFB is the only mod I'd consider assigning to a DPDT switch.

Rob,

I've experimented with this quite a bit, here is what I have found to sound best in mine. Starting from the power supply side of the amp, and working to the preamp side, (plate filter, screen filter, and preamp filter) all Sprague Atoms: 20uF/500V, 20uF/500V, 10uF/500V. The plate filter can be increased to 30uF or more, but this heightens the bass response and stiffens the attack of the notes. The screen filter can be reduced to 16uF, but I found that reducing it to 10uF made the amp sound like a flat cardboard box. I found this to be true in my 1951 GA20 as well. 10uF is the schematic value, but the amp sounds flat with that, but becomes tasty sounding again with a 16uF in that position.

At first I had used F&T electrolytics in this amp until I discovered they were causing ghost notes on some low notes.

It is kind of interesting that everyone is having such different experiences with these amps. I wonder if it is just each person's style & perceptions or if there is a decent amount of variation in these amps.

Looks like the biggest reason for the variation is that everyone has done different combinations of the mods.

It sounds like you have done all of the mods that I have, including the treble bypass on the volume control. What you are describing with your amp's tone sounds pretty much just like mine.

Turned down low, and staying clean for some time as it gets turned up, mine has a "better than blackface" clean tone. The treble bleed on the volume control has a lot to do with that, but then so do all of the other mods

Rob,

I've experimented with this quite a bit, here is what I have found to sound best in mine. Starting from the power supply side of the amp, and working to the preamp side, (plate filter, screen filter, and preamp filter) all Sprague Atoms: 20uF/500V, 20uF/500V, 10uF/500V. The plate filter can be increased to 30uF or more, but this heightens the bass response and stiffens the attack of the notes. The screen filter can be reduced to 16uF, but I found that reducing it to 10uF made the amp sound like a flat cardboard box. I found this to be true in my 1951 GA20 as well. 10uF is the schematic value, but the amp sounds flat with that, but becomes tasty sounding again with a 16uF in that position.

At first I had used F&T electrolytics in this amp until I discovered they were causing ghost notes on some low notes.

I've got plenty of 20uf Atoms, just awaiting the 10ufs and anxious to try the 20/20/10 lineup.

Interesting about the F&T ghost notes.

I was just playing the amp Hard with the Strat's Keystone bridge pup and she's really starting to open up - I had one of those rock 'n' roll sessions where it was hard to put the pick down, just some thick juicy great tone. With the GA5 vol set to 11am there's some breakup happening, at noon the volume and breakup increase dramatically, at 1pm it's really intense, at 3pm it's totally out of control, and when dimed it's basically a fuzz box.

The fun continues ...

Looks like the biggest reason for the variation is that everyone has done different combinations of the mods.

It sounds like you have done all of the mods that I have, including the treble bypass on the volume control. What you are describing with your amp's tone sounds pretty much just like mine.

Turned down low, and staying clean for some time as it gets turned up, mine has a "better than blackface" clean tone. The treble bleed on the volume control has a lot to do with that, but then so do all of the other mods

Yep, I think I've done the same mods as you, only I did not do the treble bypass. I just leave my amp at max volume. I've been controlling the volume & drive with the guitar volume. The treble bypass would help if you are rolling the amp volume down, but would make no difference when the amp is all the way up.

I believe early in the thread, there were people claiming that their stock GA5s were dark while others thought their stock GA5s were very bright. Regardless, everyone has a different perception, and these amps are a breeze to tweak exactly where you want them. Your mods helped me get mine exactly where I want it. :mrgreen:

Yep, I think I've done the same mods as you, only I did not do the treble bypass. I just leave my amp at max volume. I've been controlling the volume & drive with the guitar volume. The treble bypass would help if you are rolling the amp volume down, but would make no difference when the amp is all the way up.

I believe early in the thread, there were people claiming that their stock GA5s were dark while others thought their stock GA5s were very bright. Regardless, everyone has a different perception, and these amps are a breeze to tweak exactly where you want them. Your mods helped me get mine exactly where I want it. :mrgreen:

Exactly. If you have the volume cranked all the time, the treble bypass cap would be irrelevant.

I think that is correct that some said their amps were dark and others bright, out of the box.

Right on. Glad the mods helped to dial it in. These amps are so simple and easy to work on that experimenting goes really well.

Hey folks....could I hook my GA5 up to my Peavey Delta Blues combo speaker to hear what it sounds like? How might I go about that? It's a 16 Ohm speaker in the Peavey. I'm just looking to see what an extension cab setup might do to my volume, and since I've got no experience with extension cabs, I'd like to try some things out before I spend any cash on buying one...they are expensive, eh?!

droo

I just jammed with my harp player with my amp and it worked really well. With the surrounding noise, rolling back my guitar's volume worked well. It's a good, authentic sounding blues amp.

I have a good 20uF cap here, it's not a Srague Atom, but a US made Tech. Maybe I'll try 20uF/16uF/10uF.

I still found the amp to be a Tad dark. Using my BYOC delay brightened it a bit. I'm going to try a 47pF cap on the volume control in place of the 22pF.

Hey folks....could I hook my GA5 up to my Peavey Delta Blues combo speaker to hear what it sounds like? How might I go about that? It's a 16 Ohm speaker in the Peavey. I'm just looking to see what an extension cab setup might do to my volume, and since I've got no experience with extension cabs, I'd like to try some things out before I spend any cash on buying one...they are expensive, eh?!

droo

The GA5's RCA is factory wired at 4 ohms (yellow lead), and there is another spare OT tap (green lead) for 8 ohms. You can run a 4 or 8 ohm OT to a 16 ohm load, but you'll be compromising volume and tone. In any case, you'd need a speaker cable with 1/4" plug at one end and an RCA plug at the other.

10-4, sounds like something I don't wanna do!

Thanks again :) I gigged it last night, I think because I set it up right next to the drummers ride, I was having a hard time hearing myself on stage. It was a large banquet hall, so he was hitting really hard! Next time I'm in that situation, I'll try putting it in front of me like a vocal monitor. Through the PA, it sounded great. During quieter times, it sounded great. When he started really beating, it got lost :(
droo

for hum sheilding will this work: I also have a roll of the metal aluminum heating duct tape for furnaces, will that work to shield the amp? I noticed you said to use a seemless piece of foil, will overlapping the tape be as effective...I have it and it is already with adhesive so it would be cheap and easy. Thanks.

I notice the mechanical vibration coming form inside the amp...spring retainer or the actual harmonic vibration that is happening to the tube? Any fixes that have work for anyone on their GA-5?

for hum sheilding will this work: I also have a roll of the metal aluminum heating duct tape for furnaces, will that work to shield the amp? I noticed you said to use a seemless piece of foil, will overlapping the tape be as effective...I have it and it is already with adhesive so it would be cheap and easy. Thanks.

The thing about aluminum foil is that it can't be soldered, so you need to use one piece of foil or be prepared to bridge two pieces of foil mechanically.

I notice the mechanical vibration coming form inside the amp...spring retainer or the actual harmonic vibration that is happening to the tube? Any fixes that have work for anyone on their GA-5?

Ah, those tinkling EL84's! Even with tube spring retainers or tube dampeners most of 'em still make noise. Like the humbuzz from single coil pickups, EL84 tinkle tone is just another fly in the ointment to endure. YMMV.

Thank you. so simply overlapping the foil tape will not work? Would I hve to fold or crimp the two pieces together?
rob, hve you tried a 30uf/16uf/10uf?

Thank you. so simply overlapping the foil tape will not work?

The tape would insulate one foil from the other. The two foil sides need to touch or be mechanically strapped with another piece of foil, preferably stapled.

rob, hve you tried a 30uf/16uf/10uf?

Not yet, awaiting another shipment of caps. Since I'm currently running 20/16/16, I'll try 20/16/10 first ...

I have been toying some more with filter cap values in mine, and have figured out two things.

1. Either the 10uF Spragues that I have are from a bad batch, or that value in that model just does not sound good to me.

2. As I had already experienced, changes in values and brands of the filter caps greatly effects the tone and response. For example, change the preamp filter to 8uF and the amp gets bright and lively. Increase the value, and the tone gets fuller, more thumpy in the bass, and stiff in response. Changing the value of the others has effects as well.

At this point, I don't know what I like best.

I'm curious to continue finding out what values the rest of you decide on.

I have been toying some more with filter cap values in mine, and have figured out two things.

1. Either the 10uF Spragues that I have are from a bad batch, or that value in that model just does not sound good to me.

2. As I had already experienced, changes in values and brands of the filter caps greatly effects the tone and response. For example, change the preamp filter to 8uF and the amp gets bright and lively. Increase the value, and the tone gets fuller, more thumpy in the bass, and stiff in response. Changing the value of the others has effects as well.

At this point, I don't know what I like best.

I'm curious to continue finding out what values the rest of you decide on.

And therein lies one large issue with all things tube amps - component consistency within a device that has some inherent uniqueness ... followed by "I can't really remember what the dang thing sounded like three mods ago!" :mrgreen:

I prefer the "God" approach to tube amps. Research as much as you can, talk to people you trust, people whose tone philosophy is like yours, about things you're unsure about, buy the parts you believe will take the sound to where you want it, build the thing, fire it up and bathe in the glory of the perfection you've created.

That's how it was with my Super.

I prefer the "God" approach to tube amps. Research as much as you can, talk to people you trust, people whose tone philosophy is like yours, about things you're unsure about, buy the parts you believe will take the sound to where you want it, build the thing, fire it up and bathe in the glory of the perfection you've created.

That's how it was with my Super.

Problem is, when your doing amp designs, amp builds or amp mods to suit your or a customer's specific playing style, musical taste, favorite guitar and desired tone, it's up to you to use all of the senses God gave you to sort out what's best and be successful at it.

I would welcome divine intervention in all of that, but so far that hasn't happened to me yet.

Another problem is that our ears tend to be forgiving and can quickly become accustomed to sounds and noise. This can work against you when dialing in an amp. Couple that with sound fatigue, after listening to too many things too much (which is where I'm at right now), you can get to where you no longer know what sounds good. That can happen when you go shopping for a new stereo. After listening to so many, you no longer know what to think about what your hearing. That's when it's time to stop, and go do other non-sound related things for a few days. Which is what I'm going to do...

Hey Rob, I've got the goodies on the way to build proper DC heater supplies. I think it will work well. Let's cross our fingers. (or genuflect?)

Hey Rob, I've got the goodies on the way to build proper DC heater supplies. I think it will work well. Let's cross our fingers.

Most excellent!!! http://img.photobucket.com/albums/v82/rfdee/thumbsup.gif

What do you guys think of this little temptress?

http://www.musiciansfriend.com/product/Gibson-Goldtone-Les-Paul-Jr.-Amp?sku=481209

That's awesome. Although, when they first came out 4 years ago they were ludicrously overpriced.

I put a Weber 8A125 in my GA-5 last week and I like the tone quite a bit. It seems to me, though, that I've lost quite a bit of volume and a bit of brightness.

Does anyone know if the 8A125 is less efficient than the Goldtone/Signature speaker that came in the amp and, if so, by how much? How does the Ceramic or Alnico Blue Pup compare, in terms of efficiency, with the 8A125 and the Signature? I decided that I like the (British flavored) Eminence Red Fang in my 5E3 clone and am thinking that I might have similar speaker preferences in this tweedish amp. I'd just as soon not go on a never ending speaker quest and would welcome input.

I really do like the tone of the 8A125, but wonder if I've lost too much volume by installing this speaker. I think that I'd lean toward a very bright, very efficient speaker for this amp.

By the way, my amp is back to stock form after trying the "trinity" mods and I think that I'd like to have it a bit brighter if anyone has any suggestions.

Cassady

I put a Weber 8A125 in my GA-5 last week and I like the tone quite a bit. It seems to me, though, that I've lost quite a bit of volume and a bit of brightness.

Does anyone know if the 8A125 is less efficient than the Goldtone/Signature speaker that came in the amp and, if so, by how much? How does the Ceramic or Alnico Blue Pup compare, in terms of efficiency, with the 8A125 and the Signature? I decided that I like the (British flavored) Eminence Red Fang in my 5E3 clone and am thinking that I might have similar speaker preferences in this tweedish amp. I'd just as soon not go on a never ending speaker quest and would welcome input.

I really do like the tone of the 8A125, but wonder if I've lost too much volume by installing this speaker. I think that I'd lean toward a very bright, very efficient speaker for this amp.

By the way, my amp is back to stock form after trying the "trinity" mods and I think that I'd like to have it a bit brighter if anyone has any suggestions.

Cassady

Vintage style speakers tend to be more "snappy" and efficient than the big magnet/higher power handling speakers. You might want to contact Ted Weber for specs and recommendations.

I had a Weber Blue Pup ceramic 8" and it was snappy, ballsy and loud. I wish I still had it, as I think it might do really well in these amps. In fact, I ordered another one the other day.

The old treble bypass cap on the volume control helps with brightness at lower volumes, but has no effect when the amp is cranked.

To quote Inspector Clouseau "Not anymore..."

:confused: sniff... sniff... :cry:

Even cranked up to compete with a small PA and the harmonica player's amp, my GA-5 was not noisy.
That was with a Strat with unwound Fralin Vintage Hot pickups and no extra shielding.

1 Blonde Gibson Blem Goldtone Les Paul Jr. Amp Blonde $260.99 $260.99 Shipped 03/31/08 04:46AM

WooHoo!!!

Nothing like persistence!

:confused: sniff... sniff... :cry:

You have to keep checking the MF website every chance you get to score one of those returns.

Problem is, you're competing with Rob, I think he has 22 or 23 of these amps now, and his goal is 50. :wink:

That was with a Strat with unwound Fralin Vintage Hot pickups and no extra shielding.

Unwound?

1 Blonde Gibson Blem Goldtone Les Paul Jr. Amp Blonde $260.99 $260.99 Shipped 03/31/08 04:46AM

WooHoo!!!

Nothing like persistence!

He scores!

You have to keep checking the MF website every chance you get to score one of those returns.

Problem is, you're competing with Rob, I think he has 22 or 23 of these amps now, and his goal is 50. :wink:

Umm, only 11 so far ... but who's counting ... :mrgreen:

Got the 8A125T .... WHOA DUDES!!! ... sound bytes coming ...

Just got the Weber 8A125T in my hot li'l hands, pulled the 8F150 and stuck in the AlNiCo ... yeah baby, mo' bettah! Needless to say, the 8F150 is now on the Classifieds. :cool:

http://img.photobucket.com/albums/v82/rfdee/ga-5/ga5alnico.jpg

The Gear
Strat partscaster with Keystone bridge single coil pup, Thinline partscaster with Lawrence L298TL bridge noiseless pup. Modded GA5, trinity minus NFB, 20/16/16 Atoms, JVT couplers, 8A125T. Zoom H2 field recorder, set 12" from speaker.

For each recording the first lick is with GA5 vol at noon, 2nd and 3rd licks with vol at 11am, 11meg WAV files. Heavy Fender pick used, no picking fingers.

Strat (http://216.147.79.19/wav/8a125b.wav)

Thinline (http://216.147.79.19/wav/8a125c.wav)

http://img.photobucket.com/albums/v82/rfdee/guitars/thekids.jpg

I'd say the amp in this configuration likes the Strat Keystones better than the Tele. The third lick on the Strat had more soul to it, although the same lick on the Tele had a satisfying twang. I just had a hard time hearing through to the details on the cleanish Tele licks.

In particular, I liked how when you backed off a bit half way through the third lick with the Keystones the distortion went away and some Strat chime was revealed. You found a good sweet spot there.

It's gonna take some sorting out and tweaking, but I know I'm on the right track with this amp. Ordered out both an AlNiCo and ceramic Blue Pup for yet further taste testing - whatever pair is left over will go into a an 8 ohm 2x8 cab I'll build. Is this stuff fun or what??? :cool:

Tasty licks Rob!

Yes, that speaker sounds much better.

http://img.photobucket.com/albums/v82/rfdee/ga-5/ga5alnico.jpg


Is that the fit with a stock baffle or your custom baffle?

Hey Rob, when you ordered filter caps, did you order any 8uF?

An 8uF on the preamp makes it snappier and more responsive, and loses some of that dullness or thickness. Last night I landed 30/16/8, (no I wasn't intentionally doing a divide by 2 from left to right) which sounds sweet so far. I'm going to give it a rest though for a day or two, then come back and see what I think.

If you didn't get any 8uFs, I can send you one.

oo

Rob, is that 8A125T 20W or 30W, and how did you decide which way to go?

Rob, is that 8A125T 20W or 30W, and how did you decide which way to go?

20w - lower is better.

Is that the fit with a stock baffle or your custom baffle?

"Custom" baffle, which drops the speaker hole down 1/4".

Hey Rob, when you ordered filter caps, did you order any 8uF?

An 8uF on the preamp makes it snappier and more responsive, and loses some of that dullness or thickness. Last night I landed 30/16/8, (no I wasn't intentionally doing a divide by 2 from left to right) which sounds sweet so far. I'm going to give it a rest though for a day or two, then come back and see what I think.

If you didn't get any 8uFs, I can send you one.

No, don't have and didn't order 8uf Atoms but I think I can get one from a local friend (wink wink hint hint, Mark!). Got 30 and 10 Atoms due to arrive Wednesday.

No, don't have and didn't order 8uf Atoms but I think I can get one from a local friend (wink wink hint hint, Mark!). Got 30 and 10 Atoms due to arrive Wednesday.

Cool. With all things the same, try a 10uF in the preamp, then an 8uF and see what you think. Seems the 10uF would be just fine, but as I told you, I was unhappy with their tone in two very different amps. I'm curious what you find.

dang! i totally missed out on that deal!

i had actually been wanting to get one of those little gibson amps but was turned off by the regular price tag. when i looked at like 10pm last night they were going for $260 w/ free shipping but i waited to long to pull out the credit card and they had sold out.

super bummed.

"Custom" baffle, which drops the speaker hole down 1/4".

Rob, per your experience, would the 8A125T fit in a stock baffle and still clear the EL84 and such?

Thanks for the continuing stream of invaluable advice!!!

:cool: Just got the Weber 8A125T in my hot li'l hands, pulled the 8F150 and stuck in the AlNiCo ... yeah baby, mo' bettah! Needless to say, the 8F150 is now on the Classifieds. :cool:

http://img.photobucket.com/albums/v82/rfdee/ga-5/ga5alnico.jpg

The Gear
Strat partscaster with Keystone bridge single coil pup, Thinline partscaster with Lawrence L298TL bridge noiseless pup. Modded GA5, trinity minus NFB, 20/16/16 Atoms, JVT couplers, 8A125T. Zoom H2 field recorder, set 12" from speaker.

For each recording the first lick is with GA5 vol at noon, 2nd and 3rd licks with vol at 11am, 11meg WAV files. Heavy Fender pick used, no picking fingers.

Strat (http://216.147.79.19/wav/8a125b.wav)

Thinline (http://216.147.79.19/wav/8a125c.wav)

http://img.photobucket.com/albums/v82/rfdee/guitars/thekids.jpg
Sweet sounding Rob

Rob, per your experience, would the 8A125T fit in a stock baffle and still clear the EL84 and such?...

Nope, won't fit using the stock baffle without tweaking something - just look at how the 8A125T fits on the new baffle that drops the speaker down a goodly 1/4" ....

http://img.photobucket.com/albums/v82/rfdee/ga-5/ga5alnico.jpg

Cool. With all things the same, try a 10uF in the preamp, then an 8uF and see what you think. Seems the 10uF would be just fine, but as I told you, I was unhappy with their tone in two very different amps. I'm curious what you find.

Pulled the preamp 16uf and stuck in a 10uf (which yields all Atoms, 20/16/10) - seemed to have tightened the full spectrum of tone from low to high, lots of note bloom, great chime with Strat or Tele, punchy bass. I like this cap lineup - sounds better to me than 20/16/16 I had before.

Replaced the 10 with an 8 - with my ears and guitars, this sounded a tad shrill, *almost* on the doorstep of icepick territory, but I gave it a fair shake and played all my styles with Strat and Tele ... then went back to the 10 - ah, mo' bettah.

It's like you and I have been saying - there's a buncha uniqueness with all things amps (and guitars, etc) and to each their own - there is no right or wrong way to skin this cat.

Need to try the 30uf when I find some time later this week.

Now I know it's DANGEROUS to assume, but... "ASSUMING" the Weber 8A125 & 8A125T have the same shape and size, we've got a bit of conflicting info.

Per ROB, the 8A125T won't fit in a stock baffle since it won't clear the EL84.

Per CASSADY (see quote below), a Weber 8A125 fits just fine in a stock baffle.

What to do?!?! What to do?!?! The nice folks at Weber put a HOLD on my order for a 8A150 as I've had 2nd thoughts about it not being "balanced" enough for a variety of styles & guitars. I had settled on the 8A125 as a good middle ground btwn the 8A150 & the 8A125T which I worried will be too bright in already bright amp (for my taste).

For sheer convenience, I had hoped for a "drop in" replacement.

Hmm...

My Weber 8A125 speaker arrived today and, much to my surprise, it fits with the magnet cover in place. I won't be able to change tubes without pulling the chassis, but that's not a big deal to me.

I've also removed the rear mesh screen and "chord box" and done the "trinity" mods, but think that I may undo them at some point. Also, as I've previously mentioned, I'm running a NOS RCA 12AX7 and EL84 in this amp.

I find it difficult to describe the precise changes that the new speaker made, but I like them. I think the tone, especially when driven to power tube distortion, is "smoother" for want of a better term.

I also think that I lost some volume--not a big deal for me and it actually makes it more basement friendly when there are other people in the house. I don't know if it would be thin-walled apartment friendly or not, but it certainly isn't overly loud.

I think that the new speaker, along with the other mods, make this a more humbucker friendly amp. It still sounds good with sinle coils, too.

All in all this is a terrific amp and I'm really glad that I got one.

Sorry, no pictures as I was too lazy to get out the camera after installing the speaker; besides Rob's photos are much better than mine...

Cassady

Perhaps my lousy ASSUMPTION was wrong after all...

Per the Weber Site:

8A125:
3lb (1.36Kg)
8-1/8" (20.6cm) diameter, 4-1/8" (10.48cm) deep (no cover), 4-7/8" (12.38cm) deep (with cover).

8A125T:
3.5lb (1.6Kg)
8-1/8" (20.6cm) diameter, 4-1/4" (10.8cm) deep (no cover), 5" (12.7cm) deep (with cover).

Now I know it's DANGEROUS to assume, but... "ASSUMING" the Weber 8A125 & 8A125T have the same shape and size, we've got a bit of conflicting info.

Per ROB, the 8A125T won't fit in a stock baffle since it won't clear the EL84.

Per CASSADY (see quote below), a Weber 8A125 fits just fine in a stock baffle.

What to do?!?! What to do?!?! The nice folks at Weber put a HOLD on my order for a 8A150 as I've had 2nd thoughts about it not being "balanced" enough for a variety of styles & guitars. I had settled on the 8A125 as a good middle ground btwn the 8A150 & the 8A125T which I worried will be too bright in already bright amp (for my taste).

For sheer convenience, I had hoped for a "drop in" replacement.

Hmm...


Welp, you CAN stick in a Weber 8F150 and the big ring mag will hit the EL84 spring retainer and the front edge of the speaker will tap the chassis and you can't get the tube in or out without pulling the chassis. I'd assume the same will happen with an 8A125 (FYI, the 8A125T is the ribbed cone version of the 8A125, so the gross dimensions are the same). Also consider that there might be some differences in how the baffles were cut for each amp.

I would NOT suggest a large, robust speaker for this amp (unless you want dark, heavy bottom end saturation and yer not gonna play rock or blues with yer GA5). Been there, done that, it was a mistake.

IMO, the best GA5 Weber speakers for rock 'n' bluez might just be the Blue Pup AlNiCo or ceramic, or the CVA8, or the 8A125T.

Perhaps my lousy ASSUMPTION was wrong after all...

Per the Weber Site:

8A125:
3lb (1.36Kg)
8-1/8" (20.6cm) diameter, 4-1/8" (10.48cm) deep (no cover), 4-7/8" (12.38cm) deep (with cover).

8A125T:
3.5lb (1.6Kg)
8-1/8" (20.6cm) diameter, 4-1/4" (10.8cm) deep (no cover), 5" (12.7cm) deep (with cover).

Those speakers are dimensioned exactly the same, just different cones. And I've had enuf of them, too ....

will it fit with out mods?

will it fit with out mods?

Yes.

I just got this response from Ted...
"I'd go balls out and use an 8F125 for a very big, strong punch tone with big low end and an articulate high end."

I'm thinking either this one, or the ceramic Blue Pup. Without mods? I hope so!

Curious...why are ya'll heading for Alnico?

droo

Curious...why are ya'll heading for Alnico?

droo

No me. The Kendrick I have in this one now is ceramic, and the Weber Blue Pup I have on the way is as well.

You have to keep checking the MF website every chance you get to score one of those returns.

Problem is, you're competing with Rob, I think he has 22 or 23 of these amps now, and his goal is 50. :wink:

AWWWW... MAAANNNNNNN....... With Rob still in the market I'll NEVER get one!:cry: LOL!!!!

No me. The Kendrick I have in this one now is ceramic, and the Weber Blue Pup I have on the way is as well.

Well I'll be interested in hearing about the Blue Pup!

For fun, I ran a cord out of my GA5 input 2 and into the input of a solid state Fender amp. Interesting, but mostly...bleh. Might try the same thing into the input of my Delta Blues, see if I can't combine the breakup of the GA5 into the loud clean on the DB....use it kinda like a pedal! But, I'm too tired to uncover the beast ;) Nursing a cold...

droo

Well I'll be interested in hearing about the Blue Pup!

For fun, I ran a cord out of my GA5 input 2 and into the input of a solid state Fender amp. Interesting, but mostly...bleh. Might try the same thing into the input of my Delta Blues, see if I can't combine the breakup of the GA5 into the loud clean on the DB....use it kinda like a pedal! But, I'm too tired to uncover the beast ;) Nursing a cold...

droo

You're running the speaker output of one amp into the input of another amp? That's a serious no-no.

There is a quick and dirty mod for doing a line out on an amp like this. I'll post it if you need it.

Yikes! Thanks for the warning. What's the no-no? I read on the FDP that this was an OK method of not really slaving, but running them in parallel. Just to be clear, here's what I did...

Guitar--->input #1 of GA5
Guitar cable into GA5 input #2--->input of other amp.

I didn't access the RCA underneath.

droo

Yikes! Thanks for the warning. What's the no-no? I read on the FDP that this was an OK method of not really slaving, but running them in parallel. Just to be clear, here's what I did...

Guitar--->input #1 of GA5
Guitar cable into GA5 input #2--->input of other amp.

I didn't access the RCA underneath.

droo

No, no...that's fine.

I thought you were running the speaker output of one into the input of another. I didn't read your post very well. Sorry. :oops:

Well I'll be interested in hearing about the Blue Pup!

For fun, I ran a cord out of my GA5 input 2 and into the input of a solid state Fender amp. Interesting, but mostly...bleh. Might try the same thing into the input of my Delta Blues, see if I can't combine the breakup of the GA5 into the loud clean on the DB....use it kinda like a pedal! But, I'm too tired to uncover the beast ;) Nursing a cold...

droo

If you use an ABY box, you will be able to choose either or both amps. It will give you more control over your effects.

I've used an ABY switch and daisy chained the GA-5 with another amp with great results.

The little amp has a lot of punch. Set clean, and combined with my Vibrolux Reverb set clean, the sound is very three dimensional with a strong presence. More punch than the VR and more shimmer than the GA-5.

No, no...that's fine.

I thought you were running the speaker output of one into the input of another. I didn't read your post very well. Sorry. :oops:


Whew! I would hate to hurt my new little fella :wink:

AWWWW... MAAANNNNNNN....... With Rob still in the market I'll NEVER get one!:cry: LOL!!!!

Keep trying! On one of these MF returns, Rob will be napping, and that's when you can make your move...

Well, for better or worse, I chose to "roll the dice" and try the Weber CVA8 as shown here: http://taweber.powweb.com/weber/cva8.htm

My hope is this will be a nice "middle-ground". Balanced, smooth, not overly bright, and a little later breakup as compared to the stock Sig8. It's a 10watt speaker (vs the 15watt Sig8) and I'm frankly not certain if I'll end up with MORE or LESS volume, but I don't think that will be huge factor for me. I'll admit that I chose the AlNiCo version to make this even more of a "sonic experiment" for me because ALL my other speakers are ceramics .

I suppose I can always plug into the Weber California's in my Twin for the high-powered, big-ceramic-magnet speaker experience. Or perhaps the massive EVM-15 in my Rivera.

I'll post my impressions once I get the speaker and have a chance to try it out.

Well, for better or worse, I chose to "roll the dice" and try the Weber CVA8 as shown here: http://taweber.powweb.com/weber/cva8.htm

My hope is this will be a nice "middle-ground". Balanced, smooth, not overly bright, and a little later breakup as compared to the stock Sig8. It's a 10watt speaker (vs the 15watt Sig8) and I'm frankly not certain if I'll end up with MORE or LESS volume, but I don't think that will be huge factor for me. I'll admit that I chose the AlNiCo version to make this even more of a "sonic experiment" for me because ALL my other speakers are ceramics .

I suppose I can always plug into the Weber California's in my Twin for the high-powered, big-ceramic-magnet speaker experience. Or perhaps the massive EVM-15 in my Rivera.

I'll post my impressions once I get the speaker and have a chance to try it out.

I have one of those speakers in my 5F1. Believe it or not, I have not tried it in GA-5. Sorry.

I love it in my 5F1, and I don't want the two amps to sound too much alike, so I didn't go there. The CVA8 has a nicer sounding cone than the Sig 8S, and sound much nicer and more responsive. The Sigs always sounded kind of dull to me. The paper of the cones is awfully thick for such a small speaker. Not very articulate, but sturdy...

But, the CVA8 is a very "vintage" sounding speaker to my ears, so it may not be to everyone's taste.

I also have a CVC8, which I did not care for in this amp. It has a different cone from the CVA8, which may be what I'm not liking, as I have the ceramic magnet Kendrick in my GA-5, that has the same cone as the CVA8, and I like it quite a bit.

Thanks "Specialty Guitars". So far, all your comments are in-line with my hopes & expectations. We'll see what happens :)

Thanks "Specialty Guitars". So far, all your comments are in-line with my hopes & expectations. We'll see what happens :)

;-)

specialty, you mentioned that it was easy to add a line out, i'm curious as to how you would wire this up, and i'll probably do it when i'm adding the 8ohm out and switching the rca to a 1/4 for convenience. thanks in advance

kid

Check the schematic for the Gibson GA-19RVT for a quick and easy line out design.

Mine will be here tomorrow - gotta start planning on how to sneak it into the house...:mrgreen:

specialty, you mentioned that it was easy to add a line out, i'm curious as to how you would wire this up, and i'll probably do it when i'm adding the 8ohm out and switching the rca to a 1/4 for convenience. thanks in advance

kid
This is from one of Gerald Weber's books. I've tried it and it works well.

Install a 1/4" jack for the line out. Run a 2.2K 1/2 watt resistor from the speaker jack's hot, to the line out jack's hot. Then add a 100 ohm 1/2 watt resistor from the line out jack to its ground. That's it.

I took the 8A125 out of my GA-5 tonight and re-installed the stock speaker. I don't think I could make a choice about which speaker I prefer in terms of tone, but in terms of volume, it's no contest--the stock speaker is MUCH louder than the 8A125.

With the 8A125 in place, could dime the amp and my Strat power tube breakup at barely louder than TV watching levels. This might be a good thing if you live in an apartment, but I wanted more volume from my amp.

I'm going to leave the stock speaker in place until I hear reports about the Blue Pups from others in this thread and then decide between one of the Blue Pups, the stock speaker and, maybe, a Signature 8S.

For those of you looking to lower the volume of a cranked tube amp, the 8A125 is good sounding, but quiet.

Cassady

This is from one of Gerald Weber's books. I've tried it and it works well.

Install a 1/4" jack for the line out. Run a 2.2K 1/2 watt resistor from the speaker jack's hot, to the line out jack's hot. Then add a 100 ohm 1/2 watt resistor from the line out jack to its ground. That's it.

I put this setup in my 5E3 clone. I like it.

I took the 8A125 out of my GA-5 tonight and re-installed the stock speaker. I don't think I could make a choice about which speaker I prefer in terms of tone, but in terms of volume, it's no contest--the stock speaker is MUCH louder than the 8A125.

With the 8A125 in place, could dime the amp and my Strat power tube breakup at barely louder than TV watching levels. This might be a good thing if you live in an apartment, but I wanted more volume from my amp.

I'm going to leave the stock speaker in place until I hear reports about the Blue Pups from others in this thread and then decide between one of the Blue Pups, the stock speaker and, maybe, a Signature 8S.

For those of you looking to lower the volume of a cranked tube amp, the 8A125 is good sounding, but quiet.

Cassady

Yes, the Sig 8 is quite loud, but to my ears it's also harsh and grainy. So far, the 8A125T sounds middle-of-the-road between the 8F150 and the Sig 8, but has great tone. I much prefer tone over volume.

Gotta see how the AlNiCo and ceramic Blue Pups sound when they arrive next week. One or both of these could be the missing link between the Sig 8 and 8A125 ....

I took the 8A125 out of my GA-5 tonight and re-installed the stock speaker. I don't think I could make a choice about which speaker I prefer in terms of tone, but in terms of volume, it's no contest--the stock speaker is MUCH louder than the 8A125.

With the 8A125 in place, could dime the amp and my Strat power tube breakup at barely louder than TV watching levels. This might be a good thing if you live in an apartment, but I wanted more volume from my amp.

I'm going to leave the stock speaker in place until I hear reports about the Blue Pups from others in this thread and then decide between one of the Blue Pups, the stock speaker and, maybe, a Signature 8S.

For those of you looking to lower the volume of a cranked tube amp, the 8A125 is good sounding, but quiet.

Cassady


As I have reported previously I was happy with replacing the stock speaker with a vintage Jensen Alnico. :cool:

I too noticed it to be significantly lower in volume and I think smoother - but there is no way I could crank it and the Strat and not far exceed TV watching volume.

Ted Weber just increased the price on the Alnico Blue Pup 8 inch 4 ohm to $40

anyone have any other threads or sites for the Gibson GA-5...

anyone have any other threads or sites for the Gibson GA-5...


Why would you want any other site??? :wink: This one is chock FULL of great info...best thread, ever :grin:

Why would you want any other site???

I wondered that as well. ;-)

anyone have any other threads or sites for the Gibson GA-5...

Everything you could ever want to know about modifying a SE amp like the GA-5 can be found at www.sewatt.com. There are specific forums targeted at the Epi Valve Junior, Blackheart SE amps and Fender Champ. As the GA-5 circuit is almost identical to the Epi VJ circuit, you could use the VJ mods. The mods that improve the VJ are just as applicable to the GA-5. I would suggest looking at the VJ FAQ where you will find most stuff.

Everything you could ever want to know about modifying a SE amp like the GA-5 can be found at www.sewatt.com. There are specific forums targeted at the Epi Valve Junior, Blackheart SE amps and Fender Champ. As the GA-5 circuit is almost identical to the Epi VJ circuit, you could use the VJ mods. The mods that improve the VJ are just as applicable to the GA-5. I would suggest looking at the VJ FAQ where you will find most stuff.

Yeah, that's a great site - however, this thread is specific to the GA5 and delivers no-brainer GA5 mods (with step-by-step mod pictorials, some even with sound bytes) that dumb newbie amp modders like myself can actually accomplish without wading through frustrating EE tech-speak that baffles more than illuminates.

This wouldn't even be a viable GA5 mod thread without the knowledgeable input and sharing from Specialty Guitars - many thanx again, Paul, for your invaluable GA5 contributions! http://img.photobucket.com/albums/v82/rfdee/thumbsup.gif http://img.photobucket.com/albums/v82/rfdee/thumbsup.gif

This has been an educational and fun thread.

I bought my GA-5 almost as a challenge to myself. I've tried, and failed, to enjoy small tube amps in the past. I've had good ones and bad ones and had decided that a Fender Princeton Reverb was the smallest amp that I'd ever enjoy.

I bought this amp to see if there was any way that the small amp that I so desired could satisfy my needs.

Out of the box, it couldn't. A few dollars and a few mods later, I'm loving it!

...can actually accomplish without wading through frustrating EE tech-speak that baffles more than illuminates.
I think that comment is unfair. A simple test by posting a question on the www.SEWATT.com forum such as "How can I improve the sound from my Gibson GA-5 - specifically make it more Fender like?" - would result in straight forward easy to follow solid advice.

The beauty of the SEWATT forums is that, by definition, it is for newbies who want to learn and no question is too dumb to ask. There is a very open minded atmosphere at that forum. The knowledge at that site is vast and the resulting modifications that have been refined by thousands of modders, assisted by professional amp designers and old timers with a bedrock of experience, represent the pinnacle of SE EL84 design. For anyone interested in taking advantage of that, then SEWATT would be a natural place to look for information.

Another excellent place is www.ax84.com where the P1 amp has been developed as a SE EL84 amp and there is a lot of information about how to tune the sound of such an amp.

Also useful information can be found at http://www.gibson.com/products/epiphone/forum/toast.asp?sub=show&action=posts&fid=4&tid=177713

I think that comment is unfair. ...

Gee, yer missing my point.

This thread is specific to the GA5. It contains well presented mods to the GA5.

If yer not an EE or an amp guru or have had zero experience modding a tube amp, and you have a GA5, the postings on this thread can give you the instant knowledge on how to make simple GA5 mods without understanding the tech speak behind the processes, and allow yer ears to make the decision as to whether or not the mods are an improvement for You.

YMMV.

Gee, yer missing my point. This thread is specific to the GA5.
My point is that as the GA-5 circuit is so similar to the VJ circuit, then you can use what already exists and is well documented in multiple locations.

My observation is that as this thread is already well over 900 replies, and that the mods presented so far are both few and elementary, that there is still a lot to learn. I.e. 900 replies later, this thread is still in Chapter 1 of a multiple chapter book.

So in answer to zero2sixty's question "anyone have any other threads or sites for the Gibson GA-5..." I offered some sites with all the information needed.

I am somewhat baffled why anyone would with an open minded attitude would have an issue with that.

My point is that as the GA-5 circuit is so similar to the VJ circuit, then you can use what already exists and is well documented in multiple locations.

My observation is that as this thread is already well over 900 replies, and that the mods presented so far are both few and elementary, that there is still a lot to learn. I.e. 900 replies later, this thread is still in Chapter 1 of a multiple chapter book.

So in answer to zero2sixty's question "anyone have any other threads or sites for the Gibson GA-5..." I offered some sites with all the information needed.

I am somewhat baffled why anyone would with an open minded attitude would have an issue with that.

The tube amp mod site(s) you mentioned are real good stuff, I have no issue with that at all, as I've stated. By all means, one should go to other amp mod sites if one has the inclination to learn more!

IMO, this thread serves a very useful purpose in that - 1) it's right home here at TDPRI, 2) it talks about a pretty neat tube amp that sold for cheap, 3) the specific GA5 circuit mod roots are perfect for those who normally wouldn't do amp mods.

It was just such simple posts years ago regarding other amps that got me started on the tweaking and modding of existing circuits in some of my gear. I enjoy reading about them even if I don't have that particular amp. Keep 'em coming and thanks for sharing

Has anyone had problems with a cabinet or speaker buzz? It's especially noticeable on the E and A strings and neck pickup, even at low volumes. Haven't been able to find it so far which makes me think it could be the speaker. Thanks for any suggestions!

I have, big time - and it turned out to be parasitics from some instability in the circuit. The remedy is a 1.5k resistor between the preamp socket pin 7 and the signal lead that comes off the volume pot.


Sirloin, I was wondering if you'd tried Rob's suggestion on this. I'm having the same issue. Mine was a blem, and inside the box was documentation that the reason it was returned was "vibrations in chassis".

I don't want to incur the return shipping if it's an easy fix, but also don't want to void the return by soldering on it.
I wonder if affixing the resistor with clip leads might tell me anything?

hmmmm....


edit - also curious....is this a proper fix, or would this be bandaiding an issue that could be ongoing or even worsen?

One reason someone may like to see another site that has information on the same subject, would be the same reason most people prefer to explore more than one source of information. I am noticing a testiness in this thread regarding anyone who may not totally agree with a particular set of mods, or how to go about achiving the sounds they are looking for. Writing in all caps does not make any point clearer. I have enjoyed this particular thread for a while now and would hate to see it turn into an argument as to whose information is better. All information is valuable. All opinions have weight, and I for one, would like to know where I can find every scrape of new knowledge I might be seeking.

Sirloin, I was wondering if you'd tried Rob's suggestion on this. I'm having the same issue. Mine was a blem, and inside the box was documentation that the reason it was returned was "vibrations in chassis".

I don't want to incur the return shipping if it's an easy fix, but also don't want to void the return by soldering on it.
I wonder if affixing the resistor with clip leads might tell me anything?

hmmmm....


edit - also curious....is this a proper fix, or would this be bandaiding an issue that could be ongoing or even worsen?

If your problem turns out to be "vibrations in chassis" rather than instability in the circuit, there are a lot of easy remedies.

For instance, my amp came with 2 small pieces or Tolex trapped between the chassis and the cabinet to prevent vibrations. I was able to leave them out with no problem, but other amps might need them.

Sometimes it's just a matter of making sure that all the screws are tight.

Very seldom is it an issue that warrants sending the amp back, especially if you're a hands on kind of person.

... I have enjoyed this particular thread for a while now and would hate to see it turn into an argument as to whose information is better. All information is valuable. All opinions have weight, and I for one, would like to know where I can find every scrape of new knowledge I might be seeking.

Yup! As the one who started the whole tongue in cheek remark about why one would want to visit a site, let me also say that I've been reading all I can on the little beast....I've yet to find as much great info as I have here, however :wink:

On that note....anyone hooked up to an external cab lately?

droo

I just got mine in about an hour ago and it does say that the reason it was returned was "Owner didn't like it". (Whew)

I bought mine for the reason just stated a couple posts ago - I would never try and "mod" an amp if I paid $500 - $700 or $1000 but for $260, get me my soldering gun!!!

There is so much useful information here and again, one reason I decided to buy the amp was the plethora (how many times do we get to use that word?) of easy mods all nicely described here. It's a great opportunity to learn something new!

I'm just frustrated that I have to work tonight and won't be home until late. I won't get to play with it until tomorrow night!

...I don't want to incur the return shipping if it's an easy fix, but also don't want to void the return by soldering on it.

No one would even know if you've soldered in that 1.5k resistor as some of these GA5's came with them already soldered in!

I wonder if affixing the resistor with clip leads might tell me anything?

In order to stick the resistor in with clips you'll need to unsolder the signal lead ... so, what's the point in using clips?

edit - also curious....is this a proper fix, or would this be bandaiding an issue that could be ongoing or even worsen?

I don't see that as an issue - in fact, one of my GA5's had no resistor added and after awhile it became obvious that it needed to be added.



....

One reason someone may like to see another site that has information on the same subject, would be the same reason most people prefer to explore more than one source of information. I am noticing a testiness in this thread regarding anyone who may not totally agree with a particular set of mods, or how to go about achiving the sounds they are looking for. Writing in all caps does not make any point clearer. I have enjoyed this particular thread for a while now and would hate to see it turn into an argument as to whose information is better. All information is valuable. All opinions have weight, and I for one, would like to know where I can find every scrape of new knowledge I might be seeking.

I don't see any "testiness" going on. No one, particularly moi, could give a rat's pitoot whether anyone elects to make GA5 mods.

The point is that some easy mods are presented herewith for you to judge on yer own. Yer told pretty much what sonics each mod will provide and that IF yer looking to get away from "tweed tone" the simple trinity mods pretty much will do that.

Are there other GA5 mods not covered here? Of course. :roll:

This thread is a discussion about the GA5, no more and no less. Folks have chimed in about what they like and dislike about this amp. Hardware mods are discussed. Circuit mods are discussed. It covers specifics to this amp and it's not about a VJr or any other amp. It includes lotsa simple GA5 amp mod info thanx to Paul, and thanx to folks like Gee it provides routes to access other online sources for modding tube amp circuits.

My point is that as the GA-5 circuit is so similar to the VJ circuit, then you can use what already exists and is well documented in multiple locations.

My observation is that as this thread is already well over 900 replies, and that the mods presented so far are both few and elementary, that there is still a lot to learn. I.e. 900 replies later, this thread is still in Chapter 1 of a multiple chapter book.

You know Gee, you have posted about those other sites a couple of times on this thread, along with your Baby Vox schematic, and your sound clip. I'm sure that folks who want to go that direction with their GA-5 and are interested in those other sites, will go to them naturally.

There is nothing wrong with those sites. And I was joking earlier when I said "why would anyone want to go anywhere else." Of course people will want to go wherever they like to find what they want.

But there is also nothing wrong with this thread. Why can't you just let it be whatever it is and let it evolve however it evolves? There are posts about all sorts of things on here, not just few elementary mods.

Gee, you are complaining that there are just elementary mods on this thread, and others complaining that the thread is too technical, and they just want general info about the amp. The thread is what it is, and like any thread, that's the way it is.

This thread evolved more towards the guitar player not technician, who bought a GA-5 because MF had them for $299, and wanted to tweak it a bit with a mod or two and maybe a different speaker, to make it more gig, recording, or bedroom friendly. As the amp is pretty easy to work on, and quite simple, it lends itself to being worked on by players with little or no experience working on amps. This thread has evolved more in that direction, with easy, inexpensive mods to tailor the sound a bit. And there's absolutely nothing wrong with that.

So let's just let it be, and enjoy ourselves.

You know Gee, you have posted about those other sites a couple of times on this thread, along with your Baby Vox schematic, and your sound clip.
That schematic and sample are nothing to do with me. I just posted them as a demo of what can be achieved with a few dollars of components.

I'm sure that folks who want to go that direction with their GA-5 and are interested in those other sites, will go to them naturally.
But only if someone tells them about those sites and particularly is someone here asks for them as they did.

Gee, you are complaining that there are just elementary mods on this thread, and others complaining that the thread is too technical, and they just want general info about the amp. The thread is what it is, and like any thread, that's the way it is.
I wasn't complaining at all. I was observing that there appears to be an unwillingness to discuss any mods that come from "outside the circle of trust".

This thread evolved more towards the guitar player not technician, who bought a GA-5 because MF had them for $299, and wanted to tweak it a bit with a mod or two and maybe a different speaker, to make it more gig, recording, or bedroom friendly. As the amp is pretty easy to work on, and quite simple, it lends itself to being worked on by players with little or no experience working on amps. This thread has evolved more in that direction, with easy, inexpensive mods to tailor the sound a bit. And there's absolutely nothing wrong with that.
I cannot agree more - exactly what happened with the VJ.

... I wasn't complaining at all. I was observing that there appears to be an unwillingness to discuss any mods that come from "outside the circle of trust". ...

Gee, there is NO circle of trust.

There is NO unwillingness to discuss any mods for the GA5 amp.

If you have any GA5 mods, please discuss them right here on this thread, share with all of us your knowledge, show us what'cha got ... I'd love to know of other tweaks!

More like a circle of misunderstanding.
It's time to put this to rest and get this thread back on topic.

That schematic and sample are nothing to do with me. I just posted them as a demo of what can be achieved with a few dollars of components.

And there's absolutely nothing wrong with that. My point is that after checking those out, if people are interested, they will look into it and/or contact you, or post questions about them. If not, then not.


But only if someone tells them about those sites and particularly is someone here asks for them as they did.

Either way, it doesn't matter. As long as it doesn't run afoul of the moderators, post whatever you want to. It's all good. But what I, and maybe some others are perceiving, is that you seem to be trying to push and prod people to be into it. Maybe that's not correct, but that's my perception.


I wasn't complaining at all. I was observing that there appears to be an unwillingness to discuss any mods that come from "outside the circle of trust".

Gee, there is no "circle of trust". Everybody's just doing their thing. For goodness sake, post about your mods and whatever else you like. If people are interested, they will discuss and try them.


I cannot agree more - exactly what happened with the VJ.

oo

More like a circle of misunderstanding.
It's time to put this to rest and get this thread back on topic.

Don, you could not be more correct! :wink:

Anyone hook this puppy up to an external can yet??

droo

External cab?

Yes. I connected mine to my '66 Vibrolux Reverb's original Jensen 10"s. They're wire for 4 ohms. It sounded great!

I also tried it with the 8 ohm Weber 12A125 in my 5E3 clone, but, like a Fender Champ, the GA-5 sounded thin and wimpy with an 8 ohm speaker.

I also tried it with the 8 ohm Weber 12A125 in my 5E3 clone, but, like a Fender Champ, the GA-5 sounded thin and wimpy with an 8 ohm speaker.

I wonder how much of that was due to the impedence mismatch.

Anyone hook this puppy up to an external can yet??

droo

1x15 cab w/150w JenNeo, 8 ohms (using the modded GA5's 8 ohm tap) - sounded just OK, less treble bite, less overall volume, some of the snap and sparkle are kinda muted. For me, right now the 8A125T has great tone, but awaiting to see how the Blue pups will sound (hopefully, next week).

My point is that as the GA-5 circuit is so similar to the VJ circuit, then you can use what already exists and is well documented in multiple locations.

My observation is that as this thread is already well over 900 replies, and that the mods presented so far are both few and elementary, that there is still a lot to learn. I.e. 900 replies later, this thread is still in Chapter 1 of a multiple chapter book.

So in answer to zero2sixty's question "anyone have any other threads or sites for the Gibson GA-5..." I offered some sites with all the information needed.

I am somewhat baffled why anyone would with an open minded attitude would have an issue with that.

GEE, you hit the nail on the head. We all agree that this thread is great but lately I am finding the new thoughts and experiments far and few between from our experts. Most of the info here refers to the pictorial that Rob (as outstanding as they are!) posted about 2 weeks ago when we all got our NOS Gibson GA-5's at the rediculously low 299.00 musiciansfriend price. Info on this sight has slowed and I was just wondering where I could go and get some additional and perhaps new insight as to what others may be doing with their GA-5's.

The discussions around the filtering took a pretty interesting vector from the trinity mods, who knows, maybe someone else has some pretty good insight. Seems that when anyone on this thread suggests making the GA-5 more agressive ie: mesa like or Budda like, they get slammed and instructed on how to mellow out the tone.

I have found that by putting a Maxon OD-9 Pro in front of the GA-5, I can dial in the lead gain tone that I am looking for! I know that even that statement will draw a "face scrunch" from those that do not believe in using external effects...but instead of sending me back to the trinity mods (they are great ideas), anyone have any ideas on how to get my GA-5 to acheive that tone by performing internal mods so that I don't have to plug into a Moaxon OD-9 pedal?

I would like to preserve the integrity of this amp for its stock value but if there is a series of mods that will help me acheive the tone that I am looking for which will result in me keeping this little gem for the 20 years that it will take for it to become a "vintage" collectable, then it might be worth getting into the guts of the amp and tooling around.

This has been a good thread to read and follow with great input from a few guys but maybe there are few others out there with some fresh new ideas to build on the ones in this thread...

Not to "hi-jack" this thread, but...

I was poking around at Musician's Friend to see if they had any more GA5's floating around for some friends of mine, and I stumbled across a little 5 watter from Hohner, the "Hoodoo Box", model HHB5T, for $280.

http://www.musiciansfriend.com/product/Hohner-Hoodoo-Box-5W-Harmonica-Tube-Amp?sku=481664


Hand-wired 5W Class A amp designed specifically for harmonica
EL84 power tube
1 -12 AX3 preamp tube
1 - 12 AU7 preamp tube
Celestion Super 8 - 8" speaker
Spring reverb
Gain, Tone, Volume, and Reverb knobs


I wonder how this little guy stacks up against a GA5 and where it was built.

I'll admit I'd be curious to hear a guitar through it!

anyone have any ideas on how to get my GA-5 to acheive that tone by performing internal mods so that I don't have to plug into a Moaxon OD-9 pedal?

That's fairly easy.

First, do not do any of the "trinity mods".

Second, turn on the amp's power switch.

Third, find the black knob on the chassis marked "Volume" and turn it fully clockwise... :wink:

Not to "hi-jack" this thread, but...

I was poking around at Musician's Friend to see if they had any more GA5's floating around for some friends of mine, and I stumbled across a little 5 watter from Hohner, the "Hoodoo Box", model HHB5T, for $280.

http://www.musiciansfriend.com/product/Hohner-Hoodoo-Box-5W-Harmonica-Tube-Amp?sku=481664


Hand-wired 5W Class A amp designed specifically for harmonica
EL84 power tube
1 -12 AX3 preamp tube
1 - 12 AU7 preamp tube
Celestion Super 8 - 8" speaker
Spring reverb
Gain, Tone, Volume, and Reverb knobs


I wonder how this little guy stacks up against a GA5 and where it was built.

I'll admit I'd be curious to hear a guitar through it!

That looks sweet!!!!!
Why are you doing this to me??? I don't need another amp.
Its a hand wired tube amp, has reverb & a direct out to go into a PA.

anyone have any ideas on how to get my GA-5 to acheive that tone by performing internal mods so that I don't have to plug into a Moaxon OD-9 pedal?

Seriously, do not do any of those "trinity" mods.

You could add a 25uF cathode bypass cap on the cathode of the second preamp stage (pin 8 of the 12AX7 to ground).

You could also change the cathode resistors on the preamp to 1.5K, and change the plate resistors to 100K (this is how they are in a 5F1). But, the preamp actually breaks up sooner the way it is stock

At that point you could see where you're at, and go from there.

Gee posted a schematic and a sound clip a ways back in this thread, you could check out his clip, and if you want to sound more like that, you could work on some or all of the mods in his schematic.

... and where it was built.


It says "Made in China" on the back.
(Still looks like a very cool amp for the price - reverb, sirect out, hand wired, master volume)

That looks sweet!!!!!
Why are you doing this to me??? I don't need another amp.
Its a hand wired tube amp, has reverb & a direct out to go into a PA.

Uh oh...here we go again! That looks very intriguing! New thread time! :smile:

Uh oh...here we go again! That looks very intriguing! New thread time! :smile:

We don't need a new thread. We just need someone to figure out how to add a tube driven reverb to the GA-5. :mrgreen:
(It does look intriguing. Its a good thing I'm having too much fun playing my GA-5)

Uh oh...here we go again! That looks very intriguing! New thread time! :smile:

Sorry folks... didn't mean to cause any trouble. If it makes you feel any better, I read a LOUSY review here:

http://www.webervst.com/cgi-bin/talkrec.cgi?submit=lt&baseurl=http://www.webervst.com/harp&msg_num=5982

Ok ok I'm done. Anything further from me on this topic goes on ANOTHER thread. I promise!

I'll go back to patiently waiting for my CVA8 to arrive :rolleyes:

...

I'll go back to patiently waiting for my CVA8 to arrive :rolleyes:

I'm expecting a full report on that CVA8!!!

Sorry folks... didn't mean to cause any trouble. If it makes you feel any better, I read a LOUSY review here:

http://www.webervst.com/cgi-bin/talkrec.cgi?submit=lt&baseurl=http://www.webervst.com/harp&msg_num=5982

Ok ok I'm done. Anything further from me on this topic goes on ANOTHER thread. I promise!

I'll go back to patiently waiting for my CVA8 to arrive :rolleyes:

Hey Sevan, I wasn't implying that that post belonged on another thread. I meant here we go with another inexpensive amp that we all have to have, and that would mean another zillion post thread. :wink:

That's fairly easy.

First, do not do any of the "trinity mods".

Second, turn on the amp's power switch.

Third, find the black knob on the chassis marked "Volume" and turn it fully clockwise... :wink:

Very nice! Humbuckers really kick out the lows...do you have any sound clip from your 30/16/8 cap mod that you did...sounds like that might help?

No worries "Specialty Guitars", I got your meaning :)

But I really DO want to make sure I don't become "that guy" who takes this thread tooo far off topic.

Androo, I'll be sure to post feedback on the CVA8, but I'm a good 2-3 weeks away from having it in my GA5.

GEE, you hit the nail on the head. ...

I have found that by putting a Maxon OD-9 Pro in front of the GA-5, I can dial in the lead gain tone that I am looking for! I know that even that statement will draw a "face scrunch" from those that do not believe in using external effects...but instead of sending me back to the trinity mods (they are great ideas), anyone have any ideas on how to get my GA-5 to acheive that tone by performing internal mods so that I don't have to plug into a Moaxon OD-9 pedal?

I would like to preserve the integrity of this amp for its stock value but if there is a series of mods that will help me acheive the tone that I am looking for which will result in me keeping this little gem for the 20 years that it will take for it to become a "vintage" collectable, then it might be worth getting into the guts of the amp and tooling around.
See my post 243 earlier in this thread.

If the OD-9 gets you to where you want to be you need to tune the amp for more gain.
The following should achieve that:
1. Rewire the i/p jacks correctly to fix the lack of 1M ground reference. If you need a high low then copy any Fender Hi Lo layout (see picture below) otherwise put a 1M on the single i/p jack and use something like a 10K to loose any radio interference.
2. Replace the 2 1M resistors (R6 & R7) in the schematic in post 243 with 100Ks.
3. Replace the Plate resistors R3 & R4 with 100K. Nothing wrong with the 220K value but the 100K values make it easier to know the cathode resistor values that are tried and tested.
4. Reduce C3 to 2.2uF for single coils, 1uF for humbuckers.
5. Add C4 and try 2.2uF - big gain boost so can be put onto a switch.
6. Change R8 to 1.5K and R9 to 820 for 680 for even more crunch - big gain boost.
7. Change C5 to 1000-2000uF (25V or greater) - smooths out the distortion.
8. Add a grid stopper i.e. R15 1.5K to cancel any block distortion that be present.

The ratio of the plate resistors (R3 & R4) to the cathode resistors (R8 & R9) is important so that the pre amp is allowed to breath without being constricted and sounding harsh and fizzy.

See the Marshall schematic at the SEWATT VJ FAQ for more info. Those reversible changes should get you to where you want to be. I would suggest doing them one by one and listening to the amp so that you can fine tune it to get the distortion you want. You may or may not need all the mods - try it.

You make a good point about preserving the amp for 20 years. Just keep all the components you remove and they can be put back when you sell it or pass it on. Another thing worth doing would be to replace all the resistors with carbon film resistors - less noisy.

http://www.el34world.com/charts/images/jackwire2.jpg

I wonder how much of that was due to the impedence mismatch.

All of it, I'd guess. I've had the same result with a Champ and a different 8 ohm speaker.

I'll try my 8 ohm 12" Eminence Tonker with the amp this weekend and see if the result is similar. I'm sure it will be.

The real test would be to use the 8 ohm tap, but I don't even plan to pull the heat shrink tubing off of that.

All of it, I'd guess. I've had the same result with a Champ and a different 8 ohm speaker.

I'll try my 8 ohm 12" Eminence Tonker with the amp this weekend and see if the result is similar. I'm sure it will be.

The real test would be to use the 8 ohm tap, but I don't even plan to pull the heat shrink tubing off of that.

Well, my other 8" Weber alnico speaker that I thought about trying is 8 ohm. So if I get around to trying it out, that heat shrink tubing is coming off mine.

It would make it more useful to me anyway since all my other amps and my 212 cab are all 8 ohm.

(Then again, I've got it sounding how I like it with the original speaker, so why mess with it?)

Well, my other 8" Weber alnico speaker that I thought about trying is 8 ohm. So if I get around to trying it out, that heat shrink tubing is coming off mine.

It would make it more useful to me anyway since all my other amps and my 212 cab are all 8 ohm.

(Then again, I've got it sounding how I like it with the original speaker, so why mess with it?)


It'd make sense to allow for the 8ohm OT tap on the GA5 if those are the prime speakers you'll be using. Or better yet - drill a 1/4" hole in the chassis bottom, near the RCA jack, replace the RCA jack with a 1/4" Switchcraft jack, screw in a SPDT mini switch to the new 1/4" hole ya just drilled, wire the middle terminal on the switch to the hot side of the Switchcraft jack, wire the yellow OT hot wire to one side of the SPDT switch and the green OT hot wire to the other side of the switch, now you can select either 4 or 8 ohms output to the jack. :cool:

It'd make sense to allow for the 8ohm OT tap on the GA5 if those are the prime speakers you'll be using. Or better yet - drill a 1/4" hole in the chassis bottom, near the RCA jack, replace the RCA jack with a 1/4" Switchcraft jack, screw in a SPDT mini switch to the new 1/4" hole ya just drilled, wire the middle terminal on the switch to the hot side of the Switchcraft jack, wire the yellow OT hot wire to one side of the SPDT switch and the green OT hot wire to the other side of the switch, now you can select either 4 or 8 ohms output to the jack. :cool:

I'm not big on drilling new holes in the chassis.

My thought was to switch the existing jack to the 8 ohm tap if I end up liking the 8 ohm 8" alnico speaker in there, then I can use an adapter if I want to run any of my other 8 om setups.

I just don't know if I'd like the alnico better than the stock one that is in there. Right now, I just put a mic on the amp and mix it in with my vocals in my 400W powered cab, so I don't really need to push any other speakers. My desire to push the other speakers, is just to see how it sounds through my other speakers when the impedence is matched.

I've also got a Weber minimass that somehow "magically" corrects the impedence for you if you want to try out different speaker impedences. I've never seen a schematic of the minimass though so I'm not exactly sure how that would work if the minimass volume is all the way up (no attenuation).

Very nice! Humbuckers really kick out the lows...do you have any sound clip from your 30/16/8 cap mod that you did...sounds like that might help?

Thought you might like that. :wink:

Sorry, no clips. I downloaded some free program to record, and bought a condenser mic of some sort thinking it would be better than my old SM58s, and tried like hell to to record an amp demo track. Everything we did sounded LAME city. I kind of got discouraged after a few tries and shelved the idea.

I have several buddies with recording setups, but due to schedules and Murphy, it never seems to fall into place.

I still haven't decided n the filter caps. The preamp cap possible has the most noticeable effect. In general terms, the higher the value, the less bass and dynamics, with a more flat sound. The lower the value, the more bass, faster response and dynamics, and the treble can become a bit raspy. I have to agree with Rob that though the response with an 8uF in the preamp is very dynamic, the treble does become a bit raspy. So I'm kind of stuck between 10uF and 16uF, though 16uF seems kind of flat.

Of course, YMMV.

Right now, the 22/16/10 Atom lineup works best of all for my main GA5, considering the guitars I use (Teles and Strats) and how I play (mostly fingerstyle) and what I play (an eclectic potpourri of bluez and jazz and "world age").

...an eclectic potpourri...

Wow! You use your tongue prettier than a $20 ... Oops I can't say that here! :wink:

See my post 243 earlier in this thread.

If the OD-9 gets you to where you want to be you need to tune the amp for more gain.
The following should achieve that:
1. Rewire the i/p jacks correctly to fix the lack of 1M ground reference. If you need a high low then copy any Fender Hi Lo layout (see picture below) otherwise put a 1M on the single i/p jack and use something like a 10K to loose any radio interference.
2. Replace the 2 1M resistors (R6 & R7) in the schematic in post 243 with 100Ks.
3. Replace the Plate resistors R3 & R4 with 100K. Nothing wrong with the 220K value but the 100K values make it easier to know the cathode resistor values that are tried and tested.
4. Reduce C3 to 2.2uF for single coils, 1uF for humbuckers.
5. Add C4 and try 2.2uF - big gain boost so can be put onto a switch.
6. Change R8 to 1.5K and R9 to 820 for 680 for even more crunch - big gain boost.
7. Change C5 to 1000-2000uF (25V or greater) - smooths out the distortion.
8. Add a grid stopper i.e. R15 1.5K to cancel any block distortion that be present.

The ratio of the plate resistors (R3 & R4) to the cathode resistors (R8 & R9) is important so that the pre amp is allowed to breath without being constricted and sounding harsh and fizzy.

See the Marshall schematic at the SEWATT VJ FAQ for more info. Those reversible changes should get you to where you want to be. I would suggest doing them one by one and listening to the amp so that you can fine tune it to get the distortion you want. You may or may not need all the mods - try it.

You make a good point about preserving the amp for 20 years. Just keep all the components you remove and they can be put back when you sell it or pass it on. Another thing worth doing would be to replace all the resistors with carbon film resistors - less noisy.

http://www.el34world.com/charts/images/jackwire2.jpg


Wow, that is great info. I think I may be over my head without following this via photos as most of my amp teaking experience has come from the insite and photo directions posted on this site. I'll open my amp up, grab the schematic and your notes and try to figure it out before I put the iron to it! I'll check out the other thread too. Thanks a lot!

Wow, that is great info. I think I may be over my head without following this via photos as most of my amp teaking experience has come from the insite and photo directions posted on this site. I'll open my amp up, grab the schematic and your notes and try to figure it out before I put the iron to it! I'll check out the other thread too. Thanks a lot!

Remember to discharge the caps before poking around in there!

How do you add an additonal cap and resistor?

How do you add an additonal cap and resistor?

Where, what values and why?

Sorry Rob, I was replying to Gee's post suggesting adding a cap and resistor, I don't know what he means.

Sorry Rob, I was replying to Gee's post suggesting adding a cap and resistor, I don't know what he means.

Neither do I. :shock:

Coupons -music123 is taking eightyrocks -15%, They are tiny amps, about the size of the Fender Champion 600, saw 2 together @ Cintiollis in Philly
Jim

Coupons -music123 is taking eightyrocks -15%, They are tiny amps, about the size of the Fender Champion 600, saw 2 together @ Cintiollis in Philly
Jim

Yeah, I know about the 15% off thingy, but what amp are you talking about and why post it here on the GA5 thread?

Yeah, I know about the 15% off thingy, but what amp are you talking about and why post it here on the GA5 thread?

SURVEY SAYS!!!!

NONE:confused:

there are no amps on the discount list.

Check out these detailed pics of the plexiglas version.

Somebody will save these for posterity, no doubt.

http://cgi.ebay.com/Gibson-Les-Paul-Junior-GA5-Amplifier_W0QQitemZ300214423753QQihZ020QQcategoryZ 10171QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

It's just the weirdest looking amp ever, eh? See through?? Really??

On another note, I've been spending time a/b'ing my GA5 with my Peavey DB115. I gotta say...of course, there is waaaay more low end and volume on the DB. But tone-wise, no contest. This little bugger SMOKES it on pure tone. And the volume ain't that too far off either. Most gigs, I check my volume pot at the end of the night,and it's on 3 or 4 on the DB, everytime. When I put it on 3 or 4 in the studio, and crank up the Gibson too, the volume difference is not too noticeable. What's much more noticeable is the difference in quality tone. I might have to get rid of the DB altogether and maybe pick up another small wattage amp to go side by side at gigs. Something different, but low wattage.

Any ideas? Pro Jr? Blackheart? Any?

droo

How do you add an additonal cap and resistor?
Specifically which resistor and which cap?

With a board such as the one used in the GA-5 you can solder and re-solder the turret (silver posts) many times. So to remove a component, unsolder one end and when the solder is melted you need to pull the component lead away from the post. Then do the same to the other end of the component.

... I might have to get rid of the DB altogether and maybe pick up another small wattage amp to go side by side at gigs. Something different, but low wattage.

Any ideas? Pro Jr? Blackheart? Any?

droo

I'm a huge fan of the Li'l Dawg Champster Special and mine compliments the GA5 in every way - great tone when daisy chained ....

http://img.photobucket.com/albums/v82/rfdee/ga-5/ga5-cs.jpg

Check out these detailed pics of the plexiglas version.

Somebody will save these for posterity, no doubt.

http://cgi.ebay.com/Gibson-Les-Paul-Junior-GA5-Amplifier_W0QQitemZ300214423753QQihZ020QQcategoryZ 10171QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

That's great!

I set my Mesa/Boogie 5:50 at 5 watts and daisy chain my GA-5 with it. The Boogie is warmer and more transparent, the GA-5 is more punchy and in your face. Whether the Boogie is set clean or dirty, the GA-5 adds substance to the tone.

Check out these detailed pics of the plexiglas version.

Somebody will save these for posterity, no doubt.

http://cgi.ebay.com/Gibson-Les-Paul-Junior-GA5-Amplifier_W0QQitemZ300214423753QQihZ020QQcategoryZ 10171QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Yuk - not a fan of plastic guitars or amps.

Yuk - not a fan of plastic guitars or amps.

Sure, it's probably not as road worthy as wood, might not sound as good as wood, will look awful with scratches and bumps, etc...

But I still like it!

Sure, it's probably not as road worthy as wood, might not sound as good as wood, will look awful with scratches and bumps, etc...

But I still like it!



Totally impractical - and very cool.






(except of course for that stupid nanny-state rear grill!)

Totally impractical - and very cool.

(except of course for that stupid nanny-state rear grill!)

BUT, there's no added power cord cubby!

Still, too dang plas-sticky for my tastes.

I'm a huge fan of the Li'l Dawg Champster Special and mine compliments the GA5 in every way - great tone when daisy chained ....

http://img.photobucket.com/albums/v82/rfdee/ga-5/ga5-cs.jpg

How are you liking daisy chaining them together? I'm assuming you're doing this with the using GA5's input #2 into the Dawg's input? When I do this, I haven't been liking the drop in volume I'm getting out the GA5, it's like plugging straight into #2 alone. Does that make sense? Is that the nature of the beast? I tried out a Morley ABY pedal last night too, that was better IMO.

droo

How are you liking daisy chaining them together?

Quite good, particularly if you separate the amps by about 4 to 6 feet.

I'm assuming you're doing this with the using GA5's input #2 into the Dawg's input?

Yep.

When I do this, I haven't been liking the drop in volume I'm getting out the GA5, it's like plugging straight into #2 alone. Does that make sense? Is that the nature of the beast?

Wasn't an issue for me - besides, you can control the volume of each amp.

I tried out a Morley ABY pedal last night too, that was better IMO.

droo

....

How are you liking daisy chaining them together? I'm assuming you're doing this with the using GA5's input #2 into the Dawg's input? When I do this, I haven't been liking the drop in volume I'm getting out the GA5, it's like plugging straight into #2 alone. Does that make sense? Is that the nature of the beast? I tried out a Morley ABY pedal last night too, that was better IMO.

droo

It would be a simple step to add a line out in your GA-5 and eliminate your problem.

I can't get a reading on the caps with my multimeter so I am curious if I am doing things right. I built a ground wire with clips. This look right?

http://randylowe.com/guitar/dsc_0001.jpg

It would be a simple step to add a line out in your GA-5 and eliminate your problem.

That's a different setup entirely. The GA-5 would drive the other amp.

When they're daisy chained like Rob and I do it the guitar signal simply passes through the first amplifier's jacks and into the other amp un-amplified. The result is similar to using an A/B/Y box in the "Y" position.

I can't get a reading on the caps with my multimeter so I am curious if I am doing things right. I built a ground wire with clips. This look right?

http://randylowe.com/guitar/dsc_0001.jpg

Yer ground in the pic is doing the drain. You can check the voltage across the cap before and after the drain.

Yer ground in the pic is doing the drain. You can check the voltage across the cap before and after the drain.


Yeah, I did check before, however the amp had been setting overnight. Yesterday I did the pull the plug while strumming and could not get a reading. It must have really drained the caps.

I did the first two of the three mods, leaving out the 47K mod. I cant really say for sure that I like it at this point. It seems the speaker is farting out past 12 O'Clock.

Time will tell.

Thanks for all the great info!

Yeah, I did check before, however the amp had been setting overnight. Yesterday I did the pull the plug while strumming and could not get a reading. It must have really drained the caps.

The strum-pull-the-plug cap drain thing has always worked for me, and I'll get zero to a few volts when metered afterwards.

I did the first two of the three mods, leaving out the 47K mod. I cant really say for sure that I like it at this point.

After making a few other mods, and swapping out speakers, I've also left out the 47k NFB. There are no rights or wrongs with amp/guitar mods, only what sounds/plays best for you.

It seems the speaker is farting out past 12 O'Clock.

The stock Sig 8 speaker has very clear limits. A more robust speaker will make yer GA5 experience SO much better. I've got some Blue Pups coming to test out - the fun never ends, eh?:cool:

Time will tell.

Thanks for all the great info!

....

The stock Sig 8 speaker has very clear limits. A more robust speaker will make yer GA5 experience SO much better. I've got some Blue Pups coming to test out - the fun never ends, eh?


I will wait and see how that works for you. I will probably pull the bass bypass mod until the speaker loosens up and then try again, or order a new speaker. I was actually tooling with the idea of building a cabinet and loading an 8 ohm 12" speaker and running through that.

Yeah, I did check before, however the amp had been setting overnight. Yesterday I did the pull the plug while strumming and could not get a reading. It must have really drained the caps.

I did the first two of the three mods, leaving out the 47K mod. I cant really say for sure that I like it at this point. It seems the speaker is farting out past 12 O'Clock.

Time will tell.

Thanks for all the great info!

You might want to clip your clip elsewhere on the chassis or the ground buss so as not to risk scratching the chassis face.

Yeah, the mod removing the high pass filter will add more bass, which may sound better at lower volumes, but may cause issues when cranked.

Like Rob said, there are no rights or wrongs. You have to see what works best for you.

Wow, this thread is still goin strong! Stop reading it a while it ago when it went mod crazy. Good stuff though. Just went for a little low volume bedroom jam. Hooked up my Fulltone OCD and Crybaby and it sounded great. No surprise. Sweet amp.

At the risk of spending months reading this thread, anyone using a different speaker?