[R-390] 60 Hz on Audio

[Jon Schlegel]

Don,

Yes.  Both are free of 60 Hz.

*********

I eliminated the mech filter switching/grounding as a culprit by 
wiring directly into the 4 kHz filter from C553 and out from the 
filter to grid of V502.  60 Hz still present.

Jon



At 10:45 PM 6/10/2009 -0400, 2002tii wrote:
>Jon wrote:
>
> >This is turning into a mystery.  Here's the rundown so far.
>
>I assume you've tried several different 5749s at V502 (and 501?).
>
>Are the cathode bias line and AGC line both free of 60 Hz hum?
>
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>Don
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