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Electrical current in Speaker wire

post #1 of 14
Thread Starter 
I have a strange situation in my house with some outdoor speakers. I have a Receiver that controls the 5.1 in my living room and a set of speakers on the patio as well as a set in the garage. The garage set is connected via Adcom separate amp that is connected but not powered. The weird thing is that when checking for right and left alignment plus polarity on the patio speakers (via the AA battery test) I get a minor shock when connecting the ends of the wire when performing the check. Plus I see a little spark as well. Didn't do any further investigating until I researched first. And I do have a junction box in the attic that use to serve as a splitter when both used to be powerede by the Adcom alone. Can the wires be somehow crossed and the voltage come from the unpowered Adcom. If so what is the simplest way to test the wires. I do have a voltage meter at my disposal.

Thanks
post #2 of 14
I would start with a safety check first. Switch your meter to AC volts then check where you saw that spark. You shouldn't see a spark from low voltage DC in the daytime. Secondly I would check for DC voltage.
You need to be more explicit about that Adcom amp. What do you mean by unpowered? Is it left over from someone else. Is it connected to both sets of speaker wires but unplugged from the wall? If the speaker wires are still connected to the Adcom, remove them and read ohms when the speakers are also not connected, assuming you now have no voltage on the wires. Later you might want to connect all four speakers and read ohms at the Adcom end while not connected to the amp, just in case their total ohms is too low.
Keep track of the order you check things and assume nothing.
post #3 of 14
Because speaker wires are indirectly (or directly) connected to the amp or receiver's chassis, any audio system with outdoor speakers should be plugged into a GFCI receptacle or circuit.
post #4 of 14
Quote:
And I do have a junction box in the attic that use to serve as a splitter

How does a junction box serve as a splitter?
What are you splitting?
post #5 of 14
Thread Starter 
The splitter was used back when I had the need to power more speakers with one amp. It would accept 4 speaker input and power up to 8 speakers. And when I say that the Adcom is unpowered I mean that it is plugged in and hooked up to the speakers but just not switched on.
post #6 of 14
Quote:
Originally Posted by moodyda View Post

I have a strange situation in my house with some outdoor speakers. I have a Receiver that controls the 5.1 in my living room and a set of speakers on the patio as well as a set in the garage. The garage set is connected via Adcom separate amp that is connected but not powered. The weird thing is that when checking for right and left alignment plus polarity on the patio speakers (via the AA battery test) I get a minor shock when connecting the ends of the wire when performing the check. Plus I see a little spark as well. Didn't do any further investigating until I researched first. And I do have a junction box in the attic that use to serve as a splitter when both used to be powerede by the Adcom alone. Can the wires be somehow crossed and the voltage come from the unpowered Adcom. If so what is the simplest way to test the wires. I do have a voltage meter at my disposal.

The spark and shock might be due to inductive kick-back from the speakers or something that has transformers or something like them, say the splitter.

I would not hold off on any safety checks like probing the lines with a voltmeter that is connected to a true ground because of this possibility.
post #7 of 14
Moodyda, is that splitter an active device, meaning it's plugged into 120 volts. If so, suspect that before anything else. In fact if your Adcom amp is capable of 4 ohm output and your four speakers are 8 ohms (likely) you don't even need that splitter.

Did you disconnect all speaker wires and read ohms? But connected to that 4 in 8 out splitter your readings may be skewed. But if you read an open, the problem lies elsewhere. Your speaker wires will be indirectly connected to 120 volts only by induction in the Adcom transformer so no GFI needed except that in the garage the amp should be plugged into a GFI protected circuit.

The lagging current of an inductive load like a speaker, even with 2 or 3 way crossovers with small capacitors won't give you a shock when they are no longer connected.

Did you read voltage with your meter, both AC and DC? If it's gone, it may have been capacitive. But if it's still there, you need to remove it.
post #8 of 14
If you haven't isolated the ampyet, do it now. Remove all wires, jumper them/splice them but remove the speaker connections from the amp entirely. I suspect the amp may be an older two wire power plug and the HOT/NEUTRAL leasds got switched and placing the hot side on a potential chassis/case ground. Mixing them at any point would show around 60 volts AC, half the line voltage, not enough to kill the average person but stranger things have happened. This can also damage the final stage of the amp you're using now.
post #9 of 14
Thread Starter 
Never mind I figured it out the voltage must be coming from the volume controls. I am not using the splitter at all now and I had forgotten that the volume controls were even there.
post #10 of 14
How does a volume control produce a voltage?
post #11 of 14
In the analog world the volume control is just a pot (variable resistor) attenuating the volume down from max to zero. If indeed you had shock initially, I wouldn't assume where it came from but rather actually verify it. So with the changes you made, verify that the voltage is actually gone.

How did you conclude that your problem was a volume control?

Also there have been others here making suggestions to help and you're not reporting back in any detail.
post #12 of 14
Thread Starter 
Isolated the amp. Assured that the splitters were not inline. Did extensive testing on the lines to determine if there was a short. The volume control was the only peice not tested. The shock mind you is e very small one at that.
post #13 of 14
Well, what's the result of the testing? Is the shock potential still there? When the speaker wire ends are all disconnected do you read infinity (ohms) between them or either one to ground?
post #14 of 14
Thread Starter 
Missed that part will run that one. Thanks
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