Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: dwinstonwood on August 27, 2025, 05:41:13 pm

Title: Bias Wiggle Tremolo with 7591?
Post by: dwinstonwood on August 27, 2025, 05:41:13 pm

Hey again, another question.
Everything I read about the 7591 says it's an easy tube to drive, like an EL84 or 6V6.
I've had great success using Bias Wiggle Tremolo with those two tubes. Shouldn't it work well with 7591's, too?
If not, do I really need to go with the AB763 Roach?

Thanks!
David

Title: Re: Bias Wiggle Tremolo with 7591?
Post by: SEL49 on August 27, 2025, 05:53:10 pm

Works very well. Look at this...

     https://sluckeyamps.com/hammond_2/AO-63.pdf

Should work fine with cathode bias too.

Title: Re: Bias Wiggle Tremolo with 7591?
Post by: dwinstonwood on August 28, 2025, 07:54:43 am

Thanks SEL49!

And, thanks for the schematic. I'm actually planning on using a Cathodyne PI, too!

David

Title: Re: Bias Wiggle Tremolo with 7591?
Post by: Sonny ReVerb on September 03, 2025, 02:11:40 pm

I used a Princeton Reverb trem with a 7591 PP fixed bias power section. It works very well.

Title: Re: Bias Wiggle Tremolo with 7591?
Post by: dwinstonwood on September 04, 2025, 12:49:55 pm

Quote from: Sonny ReVerb on September 03, 2025, 02:11:40 pm

I used a Princeton Reverb trem with a 7591 PP fixed bias power section. It works very well.

Interesting, my initial "schematic-sketch" resembles a PR front end. I didn't intend it to.