Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: jewishjay on January 26, 2026, 05:29:13 pm

Title: Tremolo Inspiration
Post by: jewishjay on January 26, 2026, 05:29:13 pm

Can anyone point to an amp that has:

1. push pull
2. cathode resistor bias
3. and tremolo

It seems like Fender only used cathode biased power in single ended tremolo amps like the Vibro Champ AA764. All the push pull amps with tremolo use LDR like the Twin Reverb and or negative grid bias like Princeton AA964 or Vibrolux 5F11. I can't find any design that uses cathode biased push pull and has tremolo. Maybe theres a good reason. It doesnt have to be Fender. Any suggestions?

Title: Re: Tremolo Inspiration
Post by: SEL49 on January 26, 2026, 06:01:12 pm

There are hundreds of amps that meet your requirements. Browse through Hoffman's schematic library, specifically Ampeg, Supro, Valco, Silvertone.
Here are a few that I have personal experience with...

https://sluckeyamps.com/supro/supro.pdf
https://sluckeyamps.com/RCA/Ampeg_J12B.pdf
https://sluckeyamps.com/18w/18w.pdf
https://sluckeyamps.com/misc/Silvertone_1482.pdf
https://sluckeyamps.com/lil_maggie/Magnatone_M2.pdf

Title: Re: Tremolo Inspiration
Post by: kagliostro on January 27, 2026, 05:06:06 am

Also VOX AC30 has

but VOX has a particoular implementation for the tremolo

Franco

Title: Re: Tremolo Inspiration
Post by: roarshock on January 27, 2026, 09:00:40 am

Gibson GA-19RVT
Gibson GA-17RVT
Swart AST

There's more, but the Fender 5E9 wiggles the phase inverter.

Title: Re: Tremolo Inspiration
Post by: bmccowan on January 27, 2026, 09:29:14 am

In addition to the Sluckey list (can't go wrong there) I can highly recommend a few:
Gibson GA-16T  Like a single channel Princeton with cathode biasing and a sweet tremolo
Gibson GA-20T - has a pentode channel and a dual triode channel
Silvertone 1482
Silvertone 1333 - All octal - has a wonderful trem

Schematics for all of these are in the Library

Title: Re: Tremolo Inspiration
Post by: jewishjay on January 27, 2026, 10:38:57 am

Thanks for all the great suggestions. I think the GA16T is closest to what I was looking for. I'm gonna do something really similar to that

Title: Re: Tremolo Inspiration
Post by: bmccowan on January 27, 2026, 12:22:29 pm

Here is a Forum discussion on two GA16T builds. One by me, one by Blooze. https://el34world.com/Forum/index.php?topic=29254.msg321797#msg321797 (https://el34world.com/Forum/index.php?topic=29254.msg321797#msg321797)
Sluckey and PRR helped me get the trem working well.

Title: Re: Tremolo Inspiration
Post by: tubeswell on January 27, 2026, 12:38:57 pm

5E9A tremolux

Title: Re: Tremolo Inspiration
Post by: johnnyreece on February 03, 2026, 01:20:20 pm

Quote from: tubeswell on January 27, 2026, 12:38:57 pm

5E9A tremolux

I dig the 5E9A, as well.  If you're interested, I had somewhat different take on this a little while back.  The essence is a 5E9A, with some boosty mods from Rob Robinette's site, some modified coupling cap values to tame flub, some tremolo mods from sluckey, and power tube options because...I wanted to?  Here's the thread with documentation:  https://el34world.com/Forum/index.php?topic=31649.msg348501#msg348501

Good luck whatever way you go!