Page 1 of 1

2:90 2:Ninety Bias mod?

Posted: Sun Aug 23, 2009 1:02 pm
by francm
Has anyone done this? I'd like to be able to adjust the bias in my 2:90 so I can try different tubes.

It looks like 2 of the tubes running at the -57 bias voltage are the ones I want to play around with since they are the Class AB pair while the other two are the class A power tubes with cathode bias. That make sense?

Re: 2:90 2:Ninety Bias mod?

Posted: Fri Aug 28, 2009 5:51 pm
by xcpointx
Would be very interested in this..

Re: 2:90 2:Ninety Bias mod?

Posted: Wed Sep 02, 2009 5:01 pm
by francm
I'm actually working on this. I'm trying to figure out how to bias the class A section separately from the Class AB section.

Re: 2:90 2:Ninety Bias mod?

Posted: Wed Sep 30, 2009 1:55 pm
by vitod
Interested in this.

Re: 2:90 2:Ninety Bias mod?

Posted: Tue Mar 22, 2011 12:44 am
by robguitargod1
I'm all over this, and have designed a bias mod. Here's the thread I just started:

http://www.grailtone.com/forum/viewtopi ... =5&t=52816

Yeah, I know this thread is 2 years old.....