Teach it the words? 😉 (sorry, I couldn’t resist)
Seriously though, it would be helpful if you could provide more information about the specific setup and/or conditions where you are experiencing the hum. Does it sound like 50/60Hz? Is it coming from the speakers or the chassis?
It’s the transformer. Take it out, mask things off, soak it in lacquer under vacuum. Then let it dry in 50degC for 24h. Fit it back with new rubber mounts.
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