A humdinger question

[hylaphone]

Hi, I'm working on an amp with completely separate filament supplies for preamp and power amp.One will have 100R CT resistors, the other will have a humdinger.Would you use the resistors for the power tubes and the humdinger for preamp? Or vice versa?Thanks --

[Merlin]

Humdinger on the preamp makes the sense

[scstill]

if you are adding humdinger on one, why not do both?
have you considered elevating the filament?
https://www.valvewizard.co.uk/heater.html

[hylaphone]

if you are adding humdinger on one, why not do both?
have you considered elevating the filament?
https://www.valvewizard.co.uk/heater.html

Yes, but I was curious if hum from filament imbalance is more of an issue with preamp tubes..I would think it gets cancelled out in a push pull stage..

[pdf64]

I suggest to DC elevate both circuits to the output valve cathode voltage.