Behringer europower pmx2000 interference

[Glyn Lyndon]

Hi There

I am new to the site and I am having a problem with my amp, everytine I turn it on there is aloud SHHHHHHH noise and what sounds like very quiet music in the back ground (you can only hear this if you turn it right up), it has never done this before. I have turned pretty much everything off in the house but it still does it and also tried plugging it in to different plugs around the house.
At first it was just one speaker and now it is both of them!
I would appreciate anybodies advice if you have the time?

Thanks

Glyn

[Jazz P Bass]

Check the power supply voltages.

[Enzo]

First, experiment some and determine WHICH controls have ANY effect on the noise. Does the master volume turn it up and down? DO any of the channel volumes turn it up or down. DO only SOME of the channels make the sound? DO any7 of the tone contols change the noise tone?

If it used to be in one speaker and now is in both, I wonder if you moved any of the pan controls or the power amp assign control or either master?

[Glyn Lyndon]

Hi guys
Thanks to both of you for replying, I have plugged the amp in different power supllies around the house and it is the same, I have also tried every dial, the master volume turns the noise up and down, when I tried swapping the speaker leads over to see if it was the speakers or leads it stayed with the same side of the amp, then all of a sudden it just started making the SHHHHH noise in both of them???
Thanks again for taking the time to reply
Glyn

[Jazz P Bass]

The power supply voltages inside the amplifier need to be checked.
For starters

[Enzo]

If the master turns it up and down, it is coming from before that master control. So the power amps are probably OK.

If ALL the input channel controls are at zero, but the master is up, is it still there? If so, the problem is after the input channels.

There4 is a push switch for the graphic, probably says EQ IN/OUT. Does that switch kill the noise? If so it would localize it to the graphic section.

Most likely you have a noisy op amp ic.