$299 Gibson tube amp - Made in USA!

[red57strat]

Originally Posted by TNO

Vintage Gibson amps used 20-10-10 for the filters and IMO that is much preferable to the triple 8s or triple 16s in vintage Fenders. The preamp isn't over filtered which makes for a livelier tone. Bumping the first filter to 30uf makes a HUGE difference. I always thought the 8" speaker was overloading with the amp cranked but it's actually inadequate filtering. I always use 30-10-10 in my builds/rebuilds.

This is what I suspected and is one of the things that I'm mosdt interested in trying in my GA-5. Replacing the first 16uF filter cap with a 30uF made a big difference in my 5E3 clone. It tightened it up quite a bit, enough that I wondered if three 22uF filter caps in the GA-5 were strangling it.

[Gee]

Originally Posted by red57strat

This is what I suspected and is one of the things that I'm mosdt interested in trying in my GA-5. Replacing the first 16uF filter cap with a 30uF made a big difference in my 5E3 clone. It tightened it up quite a bit, enough that I wondered if three 22uF filter caps in the GA-5 were strangling it.

Its very easy to try quickly. You can solder a cap (16uF or 22uF or 47uF or whatever) in parallel to each cap and try it out. I.e. just piggy back a 16uF onto the first 16uf, solder both ends and play it.

Another good thing to do is to add an additional filter stage, i.e. a 22uF or bigger with a small value resistor such as 150R to 240R before the existing first power cap. A cable tie will be OK to strap it to the first cap.

[red57strat]

Originally Posted by Gee

Its very easy to try quickly. You can solder a cap (16uF or 22uF or 47uF or whatever) in parallel to each cap and try it out. I.e. just piggy back a 16uF onto the first 16uf, solder both ends and play it.

The first filter cap in my 5E3 clone was two 16uF caps in parallel until I decided to replace them with a 30uF to neaten things up.

[ehawley]

Love this thread!! I have a 1965 GA-5. One of the sweetest amps I own, Big or small! This was the only year (maybe 66 also) that they used 2 6BQ5/EL84s and one 12AU7 as the preamp. I constantly switch the AU7 for a AV7 when I want a little more dirt. One of my best recoarding amps! Not really good for play out, but one of the best recording amps aroundIMHO.

Cheers
ED

[Jaybird]

Originally Posted by TNO

Jaybird: try reversing the OT leads-I've had the squealing problem on a new build and that fixed it.

The leads were not the problem. After testing your theory and thinking about it, I can say that the OT was properly wired. If not the amp would not have worked . In the past I have wired OTs backward by mistake and the squeal began immediatly. In the present problem, the squeal does not occur until the 47k NFB resistor is connected. It has been informative doing the various mods in this thread, but they don't all work for my amp. I removed the 22pf bypass, ,installed a 4.5M resistor on the input, kept the .1 coupling cap on the first preamp stage, and installed an 8 ohm output jack. The amp sounds great. Thanks for all of the help and good suggestions. This is one of the better threads in quite a while!

[androo]

Welp, I did one of the trio of mods! And I did not hurt myself, or the amp! I really do appreciate all the advice for us fledgling techs.

So, I lifted the 25uf cap.

I like it waaaay more than adding the putting a 12AT7 in there, that just killed it IMO. The amp is just as loud, which is important to me, but the gain is much more tame and useable farther up the dial. A little bit more headroom too. Before the mod, when I dimed the volume on my amp and the guitar, it was waaaay over the top distortion, nothing I'd ever access. Now, that same spot is still over the top for me, but not nearly as much, and doesn't take up as much real estate on the dial. Really only the last bit of the sweep.

Yahoo! I did one, now I'll see if I'll try the others?? The volume is important to me, as I am gigging this little bugger and need as much as I can get. So I may not do the other two, as it sounds like those tame things down quite a bit. The first mod leaves things just as punchy and dynamic and tweedy, but the over the top distortion is not so much!


I'm proud that I was able to do it myself, and enjoy the changes I made :) Thanks to you fine folks!

droo

[rul8agn]

Just ordered one from music123.com yesterday for $299. It said they were not in stock and that they would email me when they were. Well, I got the email that mine shipped this afternoon and will be here on Tuesday. Nice! I can't wait. I sold a Pro Jr recently and now this will be my grab-n-go/practice amp.

[reddart]

Originally Posted by Jaybird

In the past I have wired OTs backward by mistake and the squeal began immediatly. In the present problem, the squeal does not occur until the 47k NFB resistor is connected.

The squeal in the past is probably because there was already NF in the circuit...if there is no NF, then it doesn't matter what the phase of the OT is (in terms of NF induced squeal, at least). Your symptoms still look like an positive feedback issue...until you actually try it and prove it false, I'm not convinced...

[Ron C]

Droo - I lifted the 25uf cap yesterday and completely agree with your assessment. The gain is more tame and doesn't go over the top until near the end of the dial. To my ears, it's not a radical change, just a nice, subtle improvement.

I've been experiment with gigging the GA-5 unmiked (I love simple). Last week I did a bar gig with about 60-80 people in it, and while it did great, it was too much gain for some songs. Yesterday, right after the mod, I played a private party for about 200 people in a single large room. We played our usual mix of old rock/r&b/blues songs, and this time (despite having to turn up louder because of the size of the room) I had fewer tunes where I was too gainy.

So Rob and Specialtyguitars - thanks for posting the mods, the photos, and the instructions for us noobs!

Ron Caselli

[ruger9]

Just a shout out to any GA-5 owner who decides the little bugger isn't their "cup of tea", please shoot me a PM/email... I've been overcome by GAS & am looking to buy... but not for the $400-$700 prices of the one left over on the net! I got to this party WAAAAY late unfortunately...

Muchas Gracis!

[androo]

Originally Posted by ruger9

Just a shout out to any GA-5 owner who decides the little bugger isn't their "cup of tea", please shoot me a PM/email... I've been overcome by GAS & am looking to buy... but not for the $400-$700 prices of the one left over on the net! I got to this party WAAAAY late unfortunately...

Muchas Gracis!

Looks like music123 has them in stock, I'd call instead of email

[Brent Hutto]

androo,

Have you called them to check? Because the web site lists it as "E-mail me when it's in stock" and "Special Order". Sounds like they will be getting some Real Soon Now (tm) like MF. For all I know they're just another MF alias anyway...

[Joe K]

Ruger -

Did you see today's post that music123 just got some of these? This may be one of those rare times when you/we get a second chance at a great limited offer-

http://www.music123.com/Gibson-Goldt...45531.Music123

[Joe K]

Originally Posted by Brent Hutto

androo,
Sounds like they will be getting some Real Soon Now (tm) like MF.

If 123 is just an alias for MF, there may not be any more...

I talked to MF a few days ago and they (Melinda) said their computer shows ONE coming in May and it is spoken for. To me, one coming by itself sounds like a computer error. Anyway, there may be no more amps after all.

DO TAKE THE OTHERS' ADVISE AND CALL though. I did on Wednesday and somehow scored a blem at a reduced price. They gave me a shipping confirmation number, so I think I really do have one coming. Yeah!

[red57strat]

Originally Posted by androo

I'm proud that I was able to do it myself, and enjoy the changes I made :) Thanks to you fine folks!

droo

Congrats! You've just joined a fun and rewarding hobby!

[Brent Hutto]

It's all guesswork, absent any inside information, but it sure sounds like those $299 closeout amps were all built back in 2006 or early 2007. If so, Occam's Razor suggests that the simplest explanation is the most likely to be true and I'd say they were sitting on a shelf somewhere not selling at $700 so they just moved them all at $300.

It's entirely plausible that Gibson took a bit of a flyer having some amps built with premium components and (by all indications) USA labor and found that while people say they value those features they don't value them enough to actually buy the darned things at the resulting price point. The fact that a $700 amp flies off the shelf at $300 doesn't exactly obligate them to crank back up the production line.

I'll predict that some day soon Gibson will "reissue the reissue" and try to sell some Asian-made generic amps under the same model name for, say, $400 or so.

[Rob DiStefano]

Well, I did it - pretty much blew out the Sig 8 speaker with the modded GA-5. Couldn't take the low end at 1/2 to 3/4 volume and now it farts out like crazy. Thankfully, the 8F150 is due in this Tuesday.

This just confirms (for me, at least) that the GA-5 circuit is specifically tweaked to push out lotsa treble and very little bass (hence, all that raunchy "tweed tone") 'cause any decent low end (like what the trinity mods offer) would cripple the Sig 8 speaker and make for unhappy customers.

[WallyArms]

Follow the Music123 link and check out the blem they have in stock - $594.96. Or you can tell them to e-mail you when they have a non-blem in stock - the price for the non-blem is $299.

Must be a typo - the blem must be a special run relic

[WallyArms]

Originally Posted by Rob DiStefano

Well, I did it - pretty much blew out the Sig 8 speaker with the modded GA-5. Couldn't take the low end at 1/2 to 3/4 volume and now it farts out like crazy. Thankfully, the 8F150 is due in this Tuesday.

This just confirms (for me, at least) that the GA-5 circuit is specifically tweaked to push out lotsa treble and very little bass (hence, all that raunchy "tweed tone") 'cause any decent low end (like what the trinity mods offer) would cripple the Sig 8 speaker and make for unhappy customers.

This thread really drives home the point that everyone hears things differently... to some, including myself, this amp is a little on the "dark" side of the sound spectrum - to others too bright.

[red57strat]

Originally Posted by WallyArms

This thread really drives home the point that everyone hears things differently... to some, including myself, this amp is a little on the "dark" side of the sound spectrum - to others too bright.

My GA-5 my darkest amp.
My 5E3 clone, Mesa/Boogie Express 5:50, '66 Vibrolux Reverb and '68 Princeton Reverb are all capable of sounding much brighter.

[Jaybird]

To me , my GA-5 is bright compared to my 5F1. The Ga-5 has got some juice though!! Could be the difference between EL84 and 6V6 in similar circuits.

[boris bubbanov]

MF has a returned one at this point for about $ 509.00 if I understand right.

Shall we have a pool on whether anyone actually buys it at that price?

[Joe K]

Originally Posted by Rob DiStefano

Well, I did it - pretty much blew out the Sig 8 speaker with the modded GA-5. Couldn't take the low end at 1/2 to 3/4 volume and now it farts out like crazy. Thankfully, the 8F150 is due in this Tuesday.

This just confirms (for me, at least) that the GA-5 circuit is specifically tweaked to push out lotsa treble and very little bass (hence, all that raunchy "tweed tone") 'cause any decent low end (like what the trinity mods offer) would cripple the Sig 8 speaker and make for unhappy customers.

To me this means you are using the heck out of your new amp. Thanks for torture testing the amp for us Rob; hope you had a blast knocking the cone out of that little 8" speaker!