Soundstream M-1 humming noise

My friend just gave me 5 Soundstream M-1 monoblocks for free because they were just taking up room in his house. At this time I was only going to use two of them to power my two passive subwoofers in my bedroom. I connected them to the subwoofer out on my Pioneer receiver. When I turned them on I got a humming noise coming from the subwoofers. Does anybody have any suggestions on how to eliminate this?

If the hum is all you get, there is some deeper problem than I can offer assistance on.

But, if it's a background hum along with the correct signal, I'd vote for it being a grounding problem. You might try switching outlets, perhaps to one on the same circuit as the receiver. If it's a grounded (three prong) plug on the amp, you might try using a cheater plug to lift the ground, although you do this at your own risk.

I'm sure others wil lfollow up with more sugestions.

I have the two amps plugged into the same surge protector as the receiver. I will have to double check whether there was any of the correct signal coming through.

What sort of problem can occur if I were to use a cheater plug?

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Originally Posted by markw

If the hum is all you get, there is some deeper problem than I can offer assistance on.

But, if it's a background hum along with the correct signal, I'd vote for it being a grounding problem. You might try switching outlets, perhaps to one on the same circuit as the receiver. If it's a grounded (three prong) plug on the amp, you might try using a cheater plug to lift the ground, although you do this at your own risk.

I'm sure others wil lfollow up with more sugestions.

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I have put the cheater plug in and the hum has gone away. Now there is only the sound I want. Am I at any risk by putting this plug inline?

In case it helps, I have found out that these amps are very similar to the Parasound HCA-1201A. The specs are identical, the back is identical, but the front is a little different.