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pas filament supply

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yero

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Joined 2010
#1
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.
 
#2
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.
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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.
 
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