Another CBS bias circuit question

[Randall]

I have re-capped and pulled the 6550s out of this Bassman 100 amp. The 6L6s are only pulling about 10mA. What would be the way to increase that? I am seeing -73v at the diode, and -59.5v at the back side of the bias pot. My B+ with standby switchon is 467v.

https://www.thetubestore.com/lib/the...-Schematic.pdf

[52 Bill]

Reducing the value of the 15K resistor to ground that is connected to the tap of the bias balance pot will lower the bias voltage and increase the output tube current draw. Or do as some do, change that resistor to a trimpot and resistor combination and have adjustable bias.

[drewl]

Yup, bias AND balance.

[Randall]

I paralleled a 22K with the 15K, and got to 34mA with this quad, putting things at about 50%, which is about where I think a Fender of this power should be. It sounds good, and is very quiet. Thanks for the advice.