$299 Gibson tube amp - Made in USA! - Page 10

red57strat · March 8th, 2008, 03:34 PM

Quote:

Originally Posted by androo

B. solder two leads to a 2 watt/27k resistor and put some alligator clips on the ends. Clip one end of the drainer to the chassis and then, clip the other to each filter cap until it's drained. Which end of cap is the correct end for this procedure?

This is what I do, though I think my resistor is bigger.

Make sure that the alligator clips are well insulated. You'd hate to get electrocuted while trying to protect yourself from being electrocuted!

One side of the cap connects to ground, the other end connects to the circuit. Drain the end that's connected to the circuit. I leave the clips attached until I'm done working on the amp. Remember to remove them before you turn the amp back on.

Check for voltage with a meter.

Sidney Vicious · March 8th, 2008, 05:04 PM

Anybody still looking for one:

There's one for sale at 299 + shipping from Fishkill, NY, on the FDP

http://www.fenderforum.com/classified.html?ad=23877

NewOldStock · March 9th, 2008, 07:17 AM

In the past I always drained caps using a simple analog voltage meter. Digital versions don't seem to work. Place it on a high ac setting and touch the probes to both sides of a capacitor. You can watch the needle dropping as the caps are being drained. Takes about 3-5 seconds.

The resistors within are doing the same draining function as the resistor-to-ground method mentioned earlier, and you also have visual proof the act is occurring. Of course, double-checking with a digital meter is always advised.

Gee · March 9th, 2008, 07:28 AM

If someone could monitor the voltage when the power is turned off then you may find that the caps drain naturally. Otherwise you could put a resistor of about 220K (1W) across the first power cap and then the amp will drain within 20 secs or so after the amp is turned off.

It is always good life prolonging practice to check the caps voltage every time you work on it anyway.

red57strat · March 9th, 2008, 09:55 AM

Quote:

Originally Posted by Gee

If someone could monitor the voltage when the power is turned off then you may find that the caps drain naturally.

You may but not always.

The first time I ever watched an amp being serviced, the tech drained the caps but shorting them to ground with a screwdriver. It made a loud crack noise and sparks.

The amp hadn't even been plugged in since the night before.

Electrolytic caps can and often will carry lethal voltages in them even after the amp is unplugged for a long time!

Even after you've drained the caps, the voltage can come back up, even with the amp unplugged. If you leave a digital volt meter connected you can actually see this happening.

Drain the caps every time your in there!!! It's the only way to be safe!!!

Rob DiStefano · March 9th, 2008, 10:05 AM

Quote:

Originally Posted by red57strat

You may but not always.

The first time I ever watched an amp being serviced, the tech drained the caps but shorting them to ground with a screwdriver. It made a loud crack noise and sparks.

The amp hadn't even been plugged in since the night before.

Electrolytic caps can and often will carry lethal voltages in them even after the amp is unplugged for a long time!

Even after you've drained the caps, the voltage can come back up, even with the amp unplugged. If you leave a digital volt meter connected you can actually see this happening.

Drain the caps every time your in there!!! It's the only way to be safe!!!

+1

Guitarslinger1 · March 9th, 2008, 12:45 PM

Here you go Rob. For the GA5 modder who has everything, how about a power cord strain relief that fits the cord properly?

I bought a couple of these from Dynakit a year or so ago, and stumbled across them yesterday.

I've got one of your 3 pos DPDT switches on the way to add a Standby, and I think after that, and some spiffy new grill cloth, I'll call it good...

Rob DiStefano · March 9th, 2008, 01:02 PM

Quote:

Originally Posted by specialty guitars

Here you go Rob. For the GA5 modder who has everything, how about a power cord strain relief that fits the cord properly?

I bought a couple of these from Dynakit a year or so ago, and stumbled across them yesterday.

I've got one of your 3 pos DPDT switches on the way to add a Standby, and I think after that, and some spiffy new grill cloth, I'll call it good...

Hmm, both my GA-5's came with a very nice power corder retainer ...

I use Carling Progressive Circuit DPTTP switches exclusively ...

"Carling Double Pole Triple Throw PROGRESSIVE (switch image on far right)

This is a two circuit, three position switch.
In the bottom position, both circuits are off.
In the middle position. one circuit is on.
In the top position, both circuits are on.

THIS IS THE SWITCH THAT ALLOWS YOU TO
HAVE BOTH A POWER ON-OFF, AND A STANDBY
SWITCH, IN THE SAME HOLE !!!"

red57strat · March 9th, 2008, 01:06 PM

That's a great switch.

If you don't mind, please post details on the install and where to get the switch.

I'm also looking forward to hearing how an alnico speaker sounds in these amps.

Rob DiStefano · March 9th, 2008, 01:12 PM

Quote:

Originally Posted by red57strat

That's a great switch.

Nope, yer wrong - it's an AMAZING switch !!!!!!

If you don't mind, please post details on the install and where to get the switch.

Get it here - www.westlabs.com - $9 each.

I'm also looking forward to hearing how an alnico speaker sounds in these amps.

AlNiCo's rarely are my cup of tea these dayze, particularly the smaller 8" variety. It takes a really robust AlNiCo RING mag speaker (not a plug mag) to make any kinda good difference, and those kinda speakers are tres expensive.

....

Guitarslinger1 · March 9th, 2008, 01:14 PM

Quote:

Originally Posted by Rob DiStefano

Hmm, both my GA-5's came with a very nice power corder retainer ...

Mine came with a white one as well, but it didn't actually pinch the cord to hold it firmly. It was too large for the diameter of the cord, and the cord was loose inside it. No big deal, but the idea is for the clip to hold the cord firmly, and I happened to have these on hand...

Sidney Vicious · March 9th, 2008, 01:19 PM

What is the advantage of the triple switch?

To prolong tube life?

(I am much enjoying my GA-5 unmodded except for removal of the metal grates and cord box.)

Rob DiStefano · March 9th, 2008, 01:19 PM

Quote:

Originally Posted by specialty guitars

Mine came with a white one as well, but it didn't actually pinch the cord to hold it firmly. It was too large for the diameter of the cord, and the cord was loose inside it. No big deal, but the idea is for the clip to hold the cord firmly, and I happened to have these on hand...

The white ones grip the power wire pretty tight. I used make up retainers outta wide cable ties.

Rob DiStefano · March 9th, 2008, 01:22 PM

Quote:

Originally Posted by Sidney Vicious

What is the advantage of the triple switch?

To prolong tube life?

(I am much enjoying my GA-5 unmodded except for removal of the metal grates and cord box.)

It can really help to have a standby with a s/s rectified amp because that recto circuit will whack a full load to the tubies whereas a recto tube will soften the blow. The Carling switch gives you the three functions of separate on/off and standby switches, all in one switch = one less hole to drill in the control panel. Besides, it just works better/easier = down is off, middle is standby, top is on.

Rob DiStefano · March 9th, 2008, 01:37 PM

Quote:

Originally Posted by Sidney Vicious

.... (I am much enjoying my GA-5 unmodded except for removal of the metal grates and cord box.)

Dude, you've really gotta try the specialty guitars circuit mod trio.

Sidney Vicious · March 9th, 2008, 01:50 PM

Quote:

Originally Posted by Rob DiStefano

Dude, you've really gotta try the specialty guitars circuit mod trio.

They all looked very doable with my tools and ok skill level and experience poking around in amps -but I think I understood the point of them to be more headroom? Me, I like breakup . . . . will have to re-read posts . . . .

(As an aside I compared the GA-5 to my stock '68 Champ with both dimed through my Telecaster - the GA-5 is noticeably louder. As others have noted a LOUD 5 watts.)

Guitarslinger1 · March 9th, 2008, 01:52 PM

Quote:

Originally Posted by Rob DiStefano

The white ones grip the power wire pretty tight. I used make up retainers outta wide cable ties.

I think mine came with a smaller diameter cord than yours. I replace my cord, but it's the same diameter as the original.

But really, like I said, it's for the "modder with everything" as I wouldn't have paid it any mind had I not stumbled across the smaller clips that I didn't know I already had.

red57strat · March 9th, 2008, 01:59 PM

Quote:

Originally Posted by Rob DiStefano

AlNiCo's rarely are my cup of tea these dayze, particularly the smaller 8" variety. It takes a really robust AlNiCo RING mag speaker (not a plug mag) to make any kinda good difference, and those kinda speakers are tres expensive.

I've got a Weber 12A125 in my 5E3 clone that I love. I've tried others in there and they just wouldn't do. I was hoping for the same kind of thing with a Weber 8A100.
Of course, I wouldn't expect the same tone from an 8 incher, though!

Rob DiStefano · March 9th, 2008, 02:04 PM

Quote:

Originally Posted by specialty guitars

I think mine came with a smaller diameter cord than yours. I replace my cord, but it's the same diameter as the original.

But really, like I said, it's for the "modder with everything" as I wouldn't have paid it any mind had I not stumbled across the smaller clips that I didn't know I already had.

The modding bug bites hard and deep.

Rob DiStefano · March 9th, 2008, 02:08 PM

Quote:

Originally Posted by Sidney Vicious

They all looked very doable with my tools and ok skill level and experience poking around in amps -but I think I understood the point of them to be more headroom? Me, I like breakup . . . . will have to re-read posts . . . .

(As an aside I compared the GA-5 to my stock '68 Champ with both dimed through my Telecaster - the GA-5 is noticeably louder. As others have noted a LOUD 5 watts.)

Just do the mods.

It's near impossible to describe the subtleties of sonics with mere words. The mods are not at all gonna make ya lose that treble bite or volume level - it's about fattening up and smoothing out the tone and overdrive, and the NFB will quiet things down lots more.

Just do the mods.

Sidney Vicious · March 9th, 2008, 02:50 PM

Quote:

Originally Posted by Rob DiStefano

Just do the mods.

It's near impossible to describe the subtleties of sonics with mere words. The mods are not at all gonna make ya lose that treble bite or volume level - it's about fattening up and smoothing out the tone and overdrive, and the NFB will quiet things down lots more.

Just do the mods.

Aye, aye, Cap'n!

So you guys say that little resister is available at my neighborhood Radio Shack?

Will report back later this week.

Rob DiStefano · March 9th, 2008, 02:55 PM

Quote:

Originally Posted by Sidney Vicious

Aye, aye, Cap'n!

So you guys say that little resister is available at my neighborhood Radio Shack?

Will report back later this week.

Yep - 47K resistor, 1/2 watt, 5% tolerance - 99 cents for 5 of 'em.

March 9th, 2008, 12:45 PM	#367 (permalink)
Guitarslinger1 Tele-Holic Join Date: May 2005 Posts: 877	For the GA5 modder who has everything... Here you go Rob. For the GA5 modder who has everything, how about a power cord strain relief that fits the cord properly? I bought a couple of these from Dynakit a year or so ago, and stumbled across them yesterday. I've got one of your 3 pos DPDT switches on the way to add a Standby, and I think after that, and some spiffy new grill cloth, I'll call it good...

March 9th, 2008, 01:06 PM	#369 (permalink)
red57strat Tele-Afflicted Join Date: Oct 2003 Location: Massachusetts Posts: 1,070	That's a great switch. If you don't mind, please post details on the install and where to get the switch. I'm also looking forward to hearing how an alnico speaker sounds in these amps. __________________ Don

March 8th, 2008, 05:04 PM	#362 (permalink)
Sidney Vicious Tele-Holic Join Date: May 2003 Location: New Orleans, Louisiana, USA Posts: 966 6 Photos	Anybody still looking for one: There's one for sale at 299 + shipping from Fishkill, NY, on the FDP http://www.fenderforum.com/classified.html?ad=23877

March 9th, 2008, 07:17 AM	#363 (permalink)
NewOldStock Tele-Holic Join Date: Mar 2003 Location: Northern Minnesota Age: 35 Posts: 560	In the past I always drained caps using a simple analog voltage meter. Digital versions don't seem to work. Place it on a high ac setting and touch the probes to both sides of a capacitor. You can watch the needle dropping as the caps are being drained. Takes about 3-5 seconds. The resistors within are doing the same draining function as the resistor-to-ground method mentioned earlier, and you also have visual proof the act is occurring. Of course, double-checking with a digital meter is always advised.

March 9th, 2008, 07:28 AM	#364 (permalink)
Gee Tele-Meister Join Date: Mar 2006 Location: Wales Posts: 277	If someone could monitor the voltage when the power is turned off then you may find that the caps drain naturally. Otherwise you could put a resistor of about 220K (1W) across the first power cap and then the amp will drain within 20 secs or so after the amp is turned off. It is always good life prolonging practice to check the caps voltage every time you work on it anyway.

March 9th, 2008, 01:19 PM	#372 (permalink)
Sidney Vicious Tele-Holic Join Date: May 2003 Location: New Orleans, Louisiana, USA Posts: 966 6 Photos	What is the advantage of the triple switch? To prolong tube life? (I am much enjoying my GA-5 unmodded except for removal of the metal grates and cord box.)