Just bought a Gibson GA-100 and need some help

Wally

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I had it converted to a sort of Fender Bandmaster circuit 14 years ago, the tech who did recommended gutting it instead of bringing up to quirky original specs which wasn't terribly well suited for bass to begin with. Two channels; Volume, Treble and Bass controls. If I remember, the transformers are rather wimpy but that contributes to it's saggy, somewhat rich midrange sound. Cathode biased too, which sounds like it has a tube rectifier even though it's solid state rectified.
What is cathode biased….the circuit that your tech built?
Both the GA100 and GA200 are fixed biased outputs.
 

BoomTexan

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Just opened her up and it is PRISTINE inside. Took some gutshots for future searchers, but this is really incredible. No cobwebs, dirt, or dust inside. The non-electrolytic caps are all reading good ESR and look very good as well.

Heck, I can't even see any bulge on any of the electrolytics. Still going to replace them, but they look pristine as well.
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Wally

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Boom, humor an old man and explain to me how that AC power cord is wired in? My eyes cannot see what I want to see in the picture.Ok

Edit: I took a second look and saw it….thanks …
 

GlideOn-Designs

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What is cathode biased….the circuit that your tech built?
Both the GA100 and GA200 are fixed biased outputs.
Read again that the original circuit was gutted out for a Fender Bandmaster. It is not stock.

But that's another thread I don't want rob the OP of his.

I just commented on the quirky nature of them and mainly my love for the GA Speaker Cabs.
 

Wally

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Read again that the original circuit was gutted out for a Fender Bandmaster. It is not stock.

But that's another thread I don't want rob the OP of his.

I just commented on the quirky nature of them and mainly my love for the GA Speaker Cabs.

I don’t need to read again. It is a confusing post…be my guest and reread it Yourself. Sometimes a human being will understand what they want to say/write and miss the mark because they assume that others understand what goes on in another’s head.
Quirky? yes, Gibson built amps that were not as simple as Fenders. The GA100 is a great amp for what it was designed to do. It is a much more sophisticated sound. It was not meant for overdriven guitar signals. Fantastic cleans.
Your tech ruined one of a small number of very well thought out and built amps. That was your privilege to allow him to do that. Imho, that was no less a travesty than what was done to a BF Bandmaster I have here…..at least, I have the remains. A ‘tech’ gutted it and built a solid state amp in it. I am sure that he thought it was an improvement…..and maybe it was for him or the user.
Peace…
 

GlideOn-Designs

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I don’t need to read again. It is a confusing post…be my guest and reread it Yourself. Sometimes a human being will understand what they want to say/write and miss the mark because they assume that others understand what goes on in another’s head.
Quirky? yes, Gibson built amps that were not as simple as Fenders. The GA100 is a great amp for what it was designed to do. It is a much more sophisticated sound. It was not meant for overdriven guitar signals. Fantastic cleans.
Your tech ruined one of a small number of very well thought out and built amps. That was your privilege to allow him to do that. Imho, that was no less a travesty than what was done to a BF Bandmaster I have here…..at least, I have the remains. A ‘tech’ gutted it and built a solid state amp in it. I am sure that he thought it was an improvement…..and maybe it was for him or the user.
Peace…

Thinking back to 2007...I had just sold a Skylark, Discoverer, Falcon and now I wanted to try a larger Gibson amp because nobody else seemed to care about them. I saw this piggyback amp that kinda looked like the Silvertone used by Jack White and my naive mind said that it would be perfect for me and presumably have the same sound. It arrived DOA. Presumably rats had made their home it it over the years. I was 19 and broke, made the decision to make it into the closest equivalent popular amp just to have something to show for it instead of having a tech who couldn't make heads or tails of it, spending thousands trying to recreate whatever the original design was.

If it was a glorious amp for the ages, it was long ruined before any tech or teenager laid their hands on it

Moral of the story?

...

It's 2022 and it still puts a smile on my face 😄


Apologies to OP, but had to set the record straight. Carry on enjoying your gear.

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