Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: TIMBO on August 17, 2020, 03:27:04 pm

Title: Resistor Question
Post by: TIMBO on August 17, 2020, 03:27:04 pm

Hi guys, Can a 12AX7 preamp valve share a cathode resistor but have different value plate resistors.
Thanks

Title: Re: Resistor Question
Post by: shooter on August 17, 2020, 04:58:04 pm

on the DC side, don't see a problem as long as you don't exceed the tubes Max dissipation
on the signal side, unsure of the outcome  :dontknow:

Title: Re: Resistor Question
Post by: SILVERGUN on August 17, 2020, 07:38:12 pm

Quote from: shooter on August 17, 2020, 04:58:04 pm

on the signal side, unsure of the outcome  :dontknow:

You wont want to share the cathode of 2 gain stages where one stage feeds the other. This is a cause of oscillation.
If they are 2 separate signal (channel) paths then have at it.