Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: jly56 on February 21, 2015, 10:45:02 pm

Title: Stout TMB build
Post by: jly56 on February 21, 2015, 10:45:02 pm: Hi..

Just finished building one of Doug's Stout TMB. I went to fire it up and realized that I don't have a 5Y3 rectifier tube.... just some 5AR4/GZ34s. Besides have a higher B+ (higher voltage drop on the 5Y3 than the GZ34), I can't think of any reason what it shouldn't work.... but figured that I would ask the board.

I noticed in the Stout TMB build page, the top picture shows a SSR Sovtek being used, and that would have an even higher B+ than a GZ34, would it?

Thanks for your responses.

Jeff
Title: Re: Stout TMB build
Post by: sluckey on February 21, 2015, 11:16:28 pm: GZ34 will work fine. But you really want the B+ to be 350V or less. You can always knock it down with a NOS 5Y3 later if needed. I used a set of Doug's 18 watt iron and had a B+ of 342V using an EZ81.
Title: Re: Stout TMB build
Post by: jly56 on February 22, 2015, 01:18:14 am: Quote from: sluckey on February 21, 2015, 11:16:28 pm
GZ34 will work fine. But you really want the B+ to be 350V or less. You can always knock it down with a NOS 5Y3 later if needed. I used a set of Doug's 18 watt iron and had a B+ of 342V using an EZ81.

Thanks Sluckey... Will toss in a GZ34 and see where my voltages are and go from there... Never thought of a EZ81! I'm also usings Doug's iron and could have used the 6v winding!

Did you make a head or a combo? I'm trying to decide what speaker to put in the combo cab my wife (the wood worker) will build for me it.

Thanks again!
Title: Re: Stout TMB build
Post by: sluckey on February 22, 2015, 04:17:55 am: I did a combo. Mine is actually a stock 1974 Marshall 18Watt circuit.

http://home.comcast.net/~seluckey/amps/18w/18w.htm (http://home.comcast.net/~seluckey/amps/18w/18w.htm)

I have an Eminence 15" Big Ben in the cab, but I prefer the sound through my 2x12 Celestion Heritage G12H cab.