previous: Tony Anyone know of a good replacement??... -- 11/6/1998 12:59 AM

Re: 1952(?) Gibson GA20 Output Transformer

11/6/1998 9:53 AM

Bruce

Re: 1952(?) Gibson GA20 Output Transformer Well, first off I'm not a Gibson expert, but I would venture a guess that it is a class A amp with the OT having about 6K5 to 8K primary.   Since MOJO sells a knockoff of the Tweed Deluxe, also a class A 6V6 Push pull amp, for a ton of money.   I would think that OT would probably work great in any amp like this.   But, here's a rub, what is the speaker impedance in the Gibson?   I've run into more then a few of these vintage amps using a 4 ohm speaker.   If this homebrew version is not very high powered, I have had excellent results using the Hammond 125E universal OT in oddball vintage amps.   It can be run class A as it is a "gap" transformer and can run a bias of 80ma.   This OT also has multilple secondary taps and you can configure it to quite a few impedance combinations.   I've run the silly thing with a pair of low voltage 5881s in push pull class AB at well over 25 watts output with no damage.   No it might not be the best sounding OT you ever heard at super low or high freqs, but for guitars it is a pretty bang for the buck!     Bruce   Mission Amps

 

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Doc I worked on a later GA20T amp, the ... -- 11/6/1998 2:53 PM