samgraysound
Well-known member
Hi All,
I'm working on Sansui 1000 which has a hum problem. It is quiet but noticeable in the power amp, put bringing up the volume control (before the 1st preamp tube) makes it incredibly loud on both channels.
The whole unit was recapped and more within the last 5 years (not by me). There is very little B+ ripple, and I tried bypassing power filter caps to no effect. It could be grounding, but every ground point I've checked has been solid.
What else should I try?
Schem attached
I'm working on Sansui 1000 which has a hum problem. It is quiet but noticeable in the power amp, put bringing up the volume control (before the 1st preamp tube) makes it incredibly loud on both channels.
The whole unit was recapped and more within the last 5 years (not by me). There is very little B+ ripple, and I tried bypassing power filter caps to no effect. It could be grounding, but every ground point I've checked has been solid.
What else should I try?
Schem attached