Shocked by Subwoofer thru Speaker Outlets of Main Amp

[lews]

I have a JBL PSW1000 powered subwoofer. I just finished wiring a whole house audio system and when I hooked up the subwoofer using coaxial cables with rca hook ups on the end into my Denon AVR-887, amp, my home theater speaker connectors became line voltage. I've pulled the back off the sub woofer and nothing seems amiss, like a paper clip or something bridging a connection. No evidence of any problem. Any ideas?

[Mikey p]

I had the same kind of problem. I ran speaker wires up the front wall, across the room to the back through a suspended ceiling, and down the rear wall to my rear speakers. I got a jolt from the wires when I attempted to hook up the rear speakers. Using a multimeter the wires showed 32 volts. And the amp wasn't turned on. It turned out to be an induction problem from the wires running beside a couple of overhead florecent light fixtures. Rerouting the wires away from the fixtures fixed the problem. Before you hook your sub up, test the wire with a multimeter and see if there's any voltage. If so, then you have an induction problem. If any other speaker wire is running through walls, test them too. Hopefully its your sub amp causing the problem and not the wiring. Keep us posted on what you find.

[chops]

When running long runs of audio cable like that, it's always best to have the audio cables pass over electrical wiring at 90 degrees to avoid any kind of inductance from the power lines. Of course, this is if you have no other choice but to run the audio lines near power lines.

[lews]

I checked the rca outlets to the sub (at the wall) and no voltage. When I cut on the sub (without the rca wires plugged in), there is 110volts at either of the rca inputs at the back of the amp. So it's seems to be entirely within the amp, not the whole house wiring.

Any ideas?

[Mikey p]

Thank goodness it wasn't in your whole house wiring. That would have been a pain to redo. As for the amp being the problem, you should post your question in the "Solid State" forum. Better chance of someone there knowing what the problem may be.

[y8s]

do your lights play low frequency music? perhaps the wires were crossed...

[richie00boy]

Originally posted by lews
I checked the rca outlets to the sub (at the wall) and no voltage. When I cut on the sub (without the rca wires plugged in), there is 110volts at either of the rca inputs at the back of the amp. So it's seems to be entirely within the amp, not the whole house wiring.

Any ideas?

So the bit about the wiring you did is not related to any of this then. Basically you plug the sub in with no other cables connected to it, then you find 110V at it's input connectors? How are you measuring this voltage, i.e. probes from outer to inner?

[lews]

Yes that's right. It's nothing to do with the whole house wiring apparently. Just the Sub.

It's interesting on the testing. I get a line voltage reading on both inputs, and on the outside and the inside (sliding the probe in like the male of an rca would go). It seems the whole thing is hot. Oddly, the subwoofer seems to work fine.

[richie00boy]

Where are you putting your black probe for the reference? A wall earth terminal?

[lews]

I put it on the ground hole at the wall outlet (110v)