Hissing and Hum through speakers

thanks for your responses..

I have moved the Plasma to another circuit. I do have a cable box in the rack, but plugging and unplugging the power of the box as well as the coaxial from the wall, made no difference.

I have tried a different preamp and I get the same results.

The preamp (Meridian 561) has a 3-prone cord and it is plugged in to the Panamax conditioner. So are the rest of the sources. The Panamax is plugged in to one plug on a duplex outlet and the Amplifier for the fronts is plugged in to the other plug of the same outlet.

Also, there possibly seems to be some level matching issues with the 561 (45 Ohms output impedance) and the amp (23.5K ohms input impedance on the rca inputs.) I tried to reduce the gain on the front L/R outputs of the 561 (via the software) from 0db to -2 db, and I think it made a slight difference with the hissing/distortion at high levels, not sure yet...

Not sure what it means exactly...I think if I keep reducing it more I will run out of gain (enough SPL) out of my amp soon, which is weird as it is suppose to be putting out 250W at 8 ohms (so around 330W with my 6 ohm speakers?)

Is it possible that the panamax is the culprit?

that is one of their best pieces but good suggestion...

I will just plug in the CD player in the Meridian and then have the CD, the Meridian, and the amp going to the wall directly and see what the results are..

thank you

thinking about for one more second, I doubt it...with nothing plugged in to the inputs of the amp, and just the speakers plugged in to the amp, I still get the same noise and hum...I will try it anyway..

What speakers are you using and how sensitive are they?

If they are close to 100db then you may need a quieter amp.