tubed preamp off and ss amp left on?

Progress maybe. I disconnected the preamp at the amps inputs and the strangest thing happened. The left channel was silent yet the right channel had the same hum and at the same level. I then plugged the interconnects back in and the hum returned to both channels. What could be happening and what is my next logical step? I have some more speaker cables that I can try, so I think I will start there. Your help in troubleshooting is most appreciated. This is a great forum.

Audio can be compared to women as a source of great pleasure and much frustration.

have you tried what I suggested earlier? about the cable tv....

I disconnected the preamp at the amps inputs and the strangest thing happened. The left channel was silent

You have the Amp isolated from all other outside input sources. Only the 120Vac power could corrupt the amp. But as you stated the left channel was silent . Jmho that would rule out the AC as the problem.

yet the right channel had the same hum and at the same level.

Sounds like a problem in the right channel. Time to take it to the shop for repair. Did you check if the manufacture has a ask a question website?

I then plugged the interconnects back in and the hum returned to both channels.

Almost sounds like the input jacks do not share the same signal ground.

I can't see how a speaker could cause your hum unless they have powered LF drivers.

If you want to rule out 100% a speaker causing the problem, switch the right and left speaker cables at the Amp. If the hum moves to the other speaker,(still the right channel) it has to be the amp's right channel.

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