Help with a new amp

[Barrye]

Hi,

I just bought a used Perreaux 2150B and I think there are some issues with it but I want to be sure before I take it back. If someone could help I would be grateful.

I am using a Yamaha RX-V757 and have connected the front speaker pre-outs to the amp.

When I power everything up the amp I get a hum through both speakers, it is not very loud but definatley there, as I turn up the volume on the Yamaha with no source input the hum will finally get overridden by the background static.

Secondly if I disconnect the right input, (have also disconected the left but it doesn't happen), to the back of the Perreaux the hum through the right speaker gets dramatically louder, (It sounds like the feedback/hum I get when I connect my computer speakers without powering them down), I have tried different speaker wires and know it has nothing to do with those as it only does it to the right channel. I have plugged the amp directly into the wall and also into a power bar.

Is the amp faulty or am I doing something wrong?

Thanks for your help on this



Barry

 

[Dolby CP-200]

Look around for a small piece of cable and attach each end one to the Yamaha say to a screw and the other to the amplifier and see if that minimizes the humming hence its called a (ground loop) not to worry this a very common issue. Let me know if that solves the problem.

 

[Barrye]

Tried that

I attatched a piece of wire to the gnd on the back of my Yamaha amp and to a screw on the back of the amp and I still had the hum. When I disconnected the wire from the back of the amp it touched one of the speaker terminals and shot a rather large spark. I am getting worried.

 

[Dolby CP-200]

Try a different mains terminal in the house and if that fails I’m fresh out of ideas, sorry mate.

 

[jcPanny]

Amp connections

You might try swapping the channels or replacing the cable between the receiver and the amp. It is easier to swap out a bad cable than to exchange the amp.

 

[roidefromage]

try a cheater plug

If the hum is due to a ground loop, or your components are commonly grounded, you can cheaply fix this by simply adding a cheater plug. (plugging your three pin iec into a two pin iec plug - Home Depot -69cents) This should break the ground loop. If not try removing your interconnects on cable at a time and see where the humming is coming from. I hope this helps, I had to do something similar recently.

 

[zumbo]

I attatched a piece of wire to the gnd on the back of my Yamaha amp and to a screw on the back of the amp and I still had the hum. When I disconnected the wire from the back of the amp it touched one of the speaker terminals and shot a rather large spark. I am getting worried.

All power sources should be disconnected, and all equipment off, while connecting wires.

Try a combination of the ideas here.

Connect a ground wire from the receiver to the amp. This will take the place of the ground prong you have removed.

Get the cheater plug for the amp. (3 prong to 2 prong) Connect the amp to the main wall outlet, not the power bar. (after all connections are made)

Make sure there are no speakers connected to the r/l speaker outputs on the receiver. Just an idea, not saying you would be that crazy.