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System Hum Question

Hi, all. I'm trying to figure out a vexing system hum issue and came across something fairly perplexing. When I disconnect the inputs from my amplifier (but leave them connected to the preamp), the hum goes away. However, when I disconnect the inputs from the preamplifier (and leave the other end connected to the amplifier), the noise in my speakers gets louder. Why is this?

(I've tried cheater plugs, a Humbuster, plugging amp + preamp into the same outlet, and unplugging everything else in my apartment. I don't have cable, fluorescent lights, or dimmers. The hum comes and goes with no discernible pattern. I live in a large apartment building.)

Thanks for any guidance you may be able to provide.
bongeiste

Showing 2 responses by bongeiste

bongeiste OP
2 posts
 
I'll have to try those suggestions. As I don't have any good A/V stores around, I'll probably go online to get some new interconnects. I don't have a CD player yet (been using my computer via optical cable), so I won't be able to test that suggestion anytime soon. Is there any reason why this hum would be there some days and not be there other days?
bongeiste OP
2 posts
 
It's been a few days, so I'd like to partially close the loop on this issue. A few days ago, there was no hum when I turned my system on. This isn't unusual as the hum comes and goes with no discernible pattern. I also installed beefier interconnects between my amplifier and preamplifier. To address an issue raised in an earlier reply, I only have my computer hooked up to my system. I don't have any other components right now. The computer is attached via TOSLink to my preamp. One night when my system was humming, I shut my computer down and unplugged it from the wall. The humming persisted, so I surmised my computer was likely not the cause of the hum issue I was experiencing. I haven't heard anything about TOSLink being a source of hum either, so I ruled that out as a likely cause.

Fast forward to today. I'm on Day 4 with no hum. The absence of hum may simply be due to a neighbor who went on vacation or my issue may truly be solved. I won't know until more time has passed.

Thank all of you who replied. I'll certainly keep your replies in mind should the hum reassert itself.
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