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tubed preamp off and ss amp left on?

Why can't I leave my my ss amp turned on with the tubed preamp turned off? Loud hum occurs through speakers with this condition. When I had a ss preamp I could leave the amp powered all the time with the pre off. I would leave all powered up but concerned about the preamp tubes wearing prematurely. Is it a reasonable conclusion that I could leave everything powered on all the time and just change the tubes once per year?
twc
twc OP
42 posts
 
Thanks. I will try disconnecting the preamp at the amp's inputs tomorrow as Mang53 suggested and see what happens. I hadn't thought of that. The amp is pretty new so I doubt it is the ps caps. I think I have had both pre and power pc's connected to the same dedicated outlet at some point but are on different dedicated outlets currently. No cable or sat. tv connected. Will post back tomorrow evening. Thanks again.
jmcgrogan2's avatar
jmcgrogan2
6,346 posts
 
Make sure you power down your amp before you disconnect the interconnects!!!
twc OP
42 posts
 
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.
audphile1's avatar
audphile1
1,368 posts
 
have you tried what I suggested earlier? about the cable tv....
jea48
2,944 posts
 
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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