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Vintage threads from the first ten years

Gibson amp favorites

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11/8/2004 11:31 PM
JonFrum	Gibson amp favorites Have any favorite Gibson amps? I'm looking for something a little different from Tweed Fenders to build.

11/9/2004 5:04 PM

I'm considering the GA16T- simple design with 2 6V6 and tremolo- it also looks to be a very straight-forward circuit. I would use a 12DW7 for the PI (this was an excellent change to my Princeton Reverb), ensuring that the low mu side of the tube is used for the PI. Also, coupling caps would be lower values (ala Fender).
I'm also intrigued by the tone control on the GA30RVT that works on the pre-amp cathode cap- I've read that it is a "low loss" design. Perhaps more pre-amp gain could be realised?
One of the simplest classic Gibson cicuits has to be the GA8T- similar to the GA16T, but uses the readily available 6BM8 / ECL82 tube as both triode and pentode. While not high powered, you could get around 16 Watts out with the right Power supply.
In fact, I have a Univox U-45b that uses almost the same circuit; I'll probably rebuid it as a GA8t.
Bill C

11/9/2004 6:16 PM
JonFrum	Bill Great info - thanks.

11/12/2004 10:24 AM

JonFrum,
Your post prompted me to look at the Gibson amps again. I have been looking at Gibson schematics as they are definitely different from the rest of the pack. I'm not sure what you are looking for in terms of complexity etc. The GA30RVT invader looks like a beauty. What I find intersting about this guy is the active Bass and midrange.I'm a great fan of the Matchless Chieftains. In fact if you look up the chieftain schematic, the preamp arrangement, Parallel tubes aside is very similar.to the GA30RVT. I might take one of these guys on myself. always liked the 0AC regulators in leslie's, Take a peak. here's a link.
http://www1.korksoft.com/%7Eschem/gibsonheaven.htm

11/13/2004 2:37 PM
Richie	GA-77R vanguard Richie

11/14/2004 11:27 PM
Enzo	If you decide to build a Gibson circuit, do yourself a favor and lay it out yourself. The way they mount parts on both sides of the terminal board in many models is one of the most serious pains in the ass for working on. I own a few Gibsons, and have serviced many. I have to admit I have never liked the sound of any of them. For reference I like the sound of Fender amps.

11/15/2004 11:04 AM

Hi Enzo,
I have never played through a Gibson Amp. Although many of their circuits are different from the norm What do they sound like?. Are they farty, shit distortion, too hifi?. I did have a GA30invader which motorboated like hell. I gutted the amp added a 9 pin socket for the ef86 used the iron to make a Matchless DC30 preamp coupled to a cathode biased 6v6 output. I don't care for the ef86 circuit but gravitate more to the 12ax7 circuits with the interactive treble bass controls. Don't care much for the 6v6 ouput. There is enough room to squeeze in 2 more 9 pin sockets for EL84's and a switch to go between the two. I thought the GA45RVT circuit looked interesting as it has similar non-interacting tone control ciruitry similar to the Matchless Chieftain. The neon pilot lights remind of those Gibson amps with big ugly aluminum front face with the painted Gibson name. We talking this vintage for the GA45 do you know?

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