pas filament supply

[yero]

I am building the high level section for the pas-3. I out boarded the power supply. I am using two independant transformers. one for the B+ as well as for the 12V filament supply which is not a voltage doubler. My Question is do you ground the return from the two supplies together, I an getting 120HZ hum. also does the power supply chassis get bonded to the chassis of the high level chassis. Thank You anyone.

[singa]

My Question is do you ground the return from the two supplies together, I an getting 120HZ hum. also does the power supply chassis get bonded to the chassis of the high level chassis. Thank You anyone.

Hi, that depends....since you are getting hum ,that means you have
got the b+ and fillament returns connected at some point.Let's put it
this way if there is hum then separate the high b+ return and complete
it's (signal) circuit by itself.Same for heater.If there is no hum now,
only then can you combine them in a star ground point to the signal chasis.
Preferably near the exit point for the power cables.Whether you can use a star ground is dependent if the signal circuit is properly connected in the first place although it's good practice for noise reduction. Good luck.