534 amp hum

[mb9513]

Hi all: the 534 stereo amp in the 2304. I have recapped the amp, and the separate power supply. it now makes a hum very briefly as it powers up when a selection is made.  and when it shuts down at the end of the last reject cycle. the amp stays live but the power supply shuts down. the hum is clearly audible. you can almost watch the volume of the hum go lower as the 5U4 heaters go down.  it does not appear to be a mute issue.   otherwise the amp sounds great and performs well as long as there are several selections. the amp did not do this before recapping. it did not sound very good though. thanks in advance.

[Ron Rich]

One can only assume here-- (getz me in trouble every time !) --Poor/incorrect ground connection on one, or more of the filters ? Did you replace all of them using newer caps under the chassis---did you ground them to the same points ?--lead dressing--did you change any inside, or outside of the amp ? Try another 5U4--- Ron Rich