ampage Tube Amps / Music Electronics	For current discussions, please visit Music Electronics Forum.

ampage archive

Vintage threads from the first ten years

previous: Steve A. TB: &nbs... -- 5/19/2000 4:39 AM

Re: 100 ohm screengrid resitor???

5/19/2000 6:01 PM
T.B.	Re: 100 ohm screengrid resitor??? Hi Steve A., Thanks for the reply. I believe the amp was originally biased for lower current like maybe around 26 ma. I've adjusted it to run at about 35 ma and no signs of tubes turning red. Even had it up to 40 ma and no sign of red. You can feel some heat emitted though. Schematic shows a neg 60 bias voltage. I put in an adjustable pot. I may post over at the Peavey board and see what they have to say. Also have a couple of other questions, like how can they ground out a .1 uf cap in the signal chain to the tone stack and still have sufficient tone to extract some. I tried that on a tube preamp and it pretty much kills the signal. Messing with amps and learning is loads of fun! Have a great weekend, T.B.

5/19/2000 6:01 PM

T.B.

Re: 100 ohm screengrid resitor???

Hi Steve A.,

Thanks for the reply. I believe the amp was originally biased for lower current like maybe around 26 ma. I've adjusted it to run at about 35 ma and no signs of tubes turning red. Even had it up to 40 ma and no sign of red. You can feel some heat emitted though. Schematic shows a neg 60 bias voltage. I put in an adjustable pot.

I may post over at the Peavey board and see what they have to say. Also have a couple of other questions, like how can they ground out a .1 uf cap in the signal chain to the tone stack and still have sufficient tone to extract some. I tried that on a tube preamp and it pretty much kills the signal.

Messing with amps and learning is loads of fun! Have a great weekend, T.B.

Replies:

Peter S The reason they used a 100 screen g... -- 5/19/2000 11:50 PM