Fixed my humming KEF 30B subwoofer.

After doing some research, it sounded like the first place (after checking ground cable) was to replace the two output capacitors. These are aluminium electrolytic capacitors. I managed to find identical capacitors from RS.

When dismantling the amplifier in the subwoofer, I found the transistors were stuck to the chassis. Left some WD40 to soak over night and they came off.

Fortunately the capacitors were not overly glued, so they weren’t too bad to remove.

Happy to say this fixed the hum, and they now sound great again.
 

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