Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: plexi50 on October 19, 2023, 09:44:59 am

Title: Identifying This Gibson Amp With Tremelo
Post by: plexi50 on October 19, 2023, 09:44:59 am
I am having trouble identifying this GA Gibson amplifier. It is wore off after GA. I have looked at many schematics and the GA 40 is what i have for the tube layout. But if i go online to find a pic of the front panel i see more knobs than this amp. 4 knobs is what this amp has.
Title: Re: Identifying This Gibson Amp With Tremelo
Post by: plexi50 on October 19, 2023, 09:47:06 am
Tube Arraignment. (3) 6SJ7 / (1) 6SN7 / (3) 6V6GT / (1) 5V4GB. Looks like a 1953 GA 40 from the GA 40 schematic. PT VOLTAGES FOR PRIMARY AND HEATER FILAMENT ARE GOOD. Found in garbage can.
Title: Re: Identifying This Gibson Amp With Tremelo
Post by: plexi50 on October 19, 2023, 10:40:38 am
From what i have found they made 2 different versions of the GA 40.
Title: Re: Identifying This Gibson Amp With Tremelo
Post by: sluckey on October 19, 2023, 10:44:37 am
This schematic matches your amp...

     https://el34world.com/charts/Schematics/files/Gibson/Gibson_ga_40v1.pdf
Title: Re: Identifying This Gibson Amp With Tremelo
Post by: rafe on October 19, 2023, 11:12:51 am
(https://originalvintageguitars.com/wp-content/uploads/2022/11/1953-gibson-ga-40-les-paul-amplifier-004.jpg)
Title: Re: Identifying This Gibson Amp With Tremelo
Post by: rafe on October 19, 2023, 11:32:20 am
That is an incredible find. I re-capped and repaired one last year. I use it almost every day now. Still have a few bugs to iron out but love it. Carl Perkins - Honey Don’t 1956 - YouTube (https://www.youtube.com/watch?v=C6Jxsynmuco)
Title: Re: Identifying This Gibson Amp With Tremelo
Post by: Lectroid on October 19, 2023, 11:42:53 am
Quote from: plexi50 on October 19, 2023, 09:47:06 am
Looks like a 1953 GA 40 ... Found in garbage can.

What a beautiful find!   I'm envious.
Title: Re: Identifying This Gibson Amp With Tremelo
Post by: bmccowan on October 19, 2023, 01:27:47 pm
Yup - I also rebuilt one of those as well as a more recent model with 5879s. Great amps - hard to work on, but its worth it. I had to buy mine :sad:
Do you search garbage cans often? I may need to start.
Title: Re: Identifying This Gibson Amp With Tremelo
Post by: tdvt on October 19, 2023, 01:33:47 pm
Quote from: Lectroid on October 19, 2023, 11:42:53 am
Quote from: plexi50 on October 19, 2023, 09:47:06 am
Looks like a 1953 GA 40 ... Found in garbage can.

What a beautiful find!   I'm envious.

Agreed

Lucky guy & lucky amp...
Title: Re: Identifying This Gibson Amp With Tremelo
Post by: shooter on October 19, 2023, 01:58:01 pm
Quote
Do you search garbage cans often?
My Teen S.S. class was tasked to put on a Christmas show, I notified the class to wear their best homeless cloths, we're going dumpster diving  :icon_biggrin:
was strange, none of them had ever been dumpster diving before.  We scored big, all the materials for props, costumes, they even found their own "memorable trinkets".
Title: Re: Identifying This Gibson Amp With Tremelo
Post by: rafe on October 19, 2023, 02:29:59 pm
What are you going to do with it? i
It would be an awesome head...."LESS PAUL" :l2:
Title: Re: Identifying This Gibson Amp With Tremelo
Post by: rafe on October 19, 2023, 02:41:39 pm
 :worthy1:
Title: Re: Identifying This Gibson Amp With Tremelo
Post by: rafe on October 19, 2023, 02:49:02 pm
This is a pretty good schematic for the amp you have ....
Title: Re: Identifying This Gibson Amp With Tremelo
Post by: rafe on October 19, 2023, 04:34:47 pm
I have a decent layout too, if you are interested
Title: Re: Identifying This Gibson Amp With Tremelo
Post by: Platefire on October 19, 2023, 10:40:43 pm
Great find---what were they thinking??? :w2: Our garbage disposals now are fenced in with security fence and has an attendant that manages everything that comes in and goes out. Use to it was just an open dumpster or two and you could take what you wanted but no more.

I had a 1961 GA40 Les Paul. A nice amp. Did my first tweed covering job on that one. My Son gobbled that one up:>)

https://www.flickr.com/photos/12623503@N04/1328123342/in/album-72157601876930477/
Title: Re: Identifying This Gibson Amp With Tremelo
Post by: plexi50 on October 20, 2023, 08:15:14 am
Thanks all for the interest and schematics! I am going to recap it and clean it up. There is no cabinet for it but a head cab would do. I have another amp Supro that i cant identify. For another post.
Title: Re: Identifying This Gibson Amp With Tremelo
Post by: ac427v on October 28, 2023, 12:15:31 pm
Doesn't matter if it works or not. That beauty wins on style points alone!