I recently moved to a new city and finally hooked up my home theater system. As my main speakers, I use the older model Infinity Preludes which have powered woofers.
When I plugged them in, WITH NO SPEAKER WIRES ATTACHED, I got a loud hum and picked up a local radio station.
I then moved the speakers up to my listening room where I have installed a separate circuit outlet off a new sub panel. The same problem occurred. I then them plugged them in through my PS Audio Ultimate Outlet with no improvement.
What's up? Do I need to do something different with the subpanel's grounding?
run to your radio shack and pick up those ferrite clamps, clamp the power cord to your powered speaker closest to your speakers. You are like getting RFI "RADIO" freq interference through your power cords, which are acting like antennas. My preamp did this once and ferrites cured them.
This happens when all the other components are unplugged and the speakers, without any speaker wires attached, are plugged in.
This has nothing to do with grounding or crosstalk (how could it the speakers are not connected to anything except AC) but is simply the ability of the integrated amps to pick up RFI and amplify it. This is a not uncommon problem with phonopreamps which have an even higher gain. Now it could just be that since there IS no external amp connected via the speaker terminals the internal amp is receiving the RFI through the open terminals.
What all IS attached to your speakers when you have this problem? Is anything attached except the line cord?
I have seen this happen with receivers and separates. It's called crosstalk. If you have a receiver see if the radio station that you hearing changes if you change the station on your receiver.
If it's a different station than the one your receiver is tuned to, it's probably not crosstalk.
If it is crosstalk you can tune the receiver to a dead position on the tuner. If you have separates you can power the tuner off when not using it (This is what I do).
IF they have three-prong grounded plugs, experiment by using "ground cheaters" on one or both of them. You can pick them up at any Rat-Shack or hardware store. Sounds like a possible ground loop to me.
The cheap and cheerful little amps in your speakers for your powered woofers act like tuners. They need to be better shielded. The radio signals are much stronger where you live now.
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