2. amps-preamps
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Maddening HUMMMM

In an attempt to get rid of a very loud speaker hum from my tube monoblocks, I've done everything I can possilbly think of, including the following;
Changed out Interconnects, the pre amp, and the speaker cables and the speakers. I've pluged each amp into a Lightspeed A/C filter, and then gotten rid of the filter and plugged directly into the wall w/o the filter. I've plugged the amps, via a 10 gauge extension cord into different wall outlets, including one dedicated outlet. Cheater plugs, then no cheater plugs, then different combos of cheater plugs or not. I disconnected the pre and had just the speakers cables to the speakers. I tired a different speaker. I've gotten up at 4 AM and turned off each circuit at the panel, then listened again. I even tried a different amp. I've lifted the cables off the carpeted floor. Using tape and assorted other devices, I've made certain that now power cords are anywhere near the ICs or speaker cables. All Components are on rack with carpet piercing spikes. NOTHING I DO ELIMINATES THE HUM.

This all started about six weeks ago when I rearranged my room and hooked up my system on the other side of the room. No hums before. Now the mega hum. This is no small noise. This is loud enough to hear in the next room. HELP ME, PLEASE, OR PUT ME OUT OF MY MISERY!!!!! Thanks for any advice you might offer. I've tried everything I can think of. Kolledog
kolledog
dopogue
1,773 posts
 
The one I have that still sports a price tag says $1.29. Still peanuts, I grant.
maril555
619 posts
 
Didn't he say in the original post, that it humms with only amps connected to speakers and with or without cheater plugs? Why everybody is wasting time offering implausable solutions?
I don't know the answer, but I had a very similar problems, and it turned out to be improperly routed intrachassis ground portion of the signal wire.
It doesn't explain why the amps didn't hum prior to move.
It's also quite unlikely that both amps sustained the same damage during the move.
Another thought- transformer hum?
kolledog OP
17 posts
 
Maril555 is correct in that the hum is audible even if only the amps are connected to the speakers. I disconnected the cable box, the cable modem, and the wireless router, and the hum has diminished to pre-move levels...

Now all I have to do is figure out a way to listen to hum-free tunes after dinner while my wonderful wife wants to watch the tube.

Thanks to all who read my original post and responded.
rhanson739
269 posts
 
Maril555: "Why everybody is wasting time offering implausable [sic] solutions? I don't know the answer..."

We offered "implausible solutions" because we didn't necessarily know the answer, either.

Kolledog - glad to hear that you figured out the source, and that some of the suggestions were perfectly plausible. I'd say chances are good that you moved the system closer to the TV setup... right?

I had a similar problem as my rig is close to a new plasma TV (no choice), but it was confusing as I had just received an amp upgrade, so I wasn't sure where it was coming from at first - I thought it was the amp. I now have the TV gear hooked up to an APC UPS, which I can turn off with the push of a button when I want to listen. It takes a while for the TV's clock and Guide to reset, but I don't really mind.
ait
480 posts
 
I had a similar issue with my system and it was the cable line. I tried the $59.00 Jensen isolation transformers but I couldn't get any picture on my digital cable (Verizon FIOS) with them installed. Got the channel guide, but none of the channels would show on the screen. Had to resort to a cheater plug on the preamp (until I can think of a better way).
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