Problem with hum in the pre-amp

I recently purchased a Parasound PLD-1100 pre-amp and right away I noticed an annoying hum on either side. It's plugged into an AudioPrism Power Foundation AC line conditioner. The hum is there whether the pre-amp is turn on or not. As long as it's plugged in, it hums. Only when I cut power to the line conditioner does the hum stop. I tried plugging it into another AC conditioner and the hum is still there. I also tried plugging it staight into the wall outlet; still hums. Nothing else hums, including the amp.

It has a remote and I'm wondering if the motorized volume control switch might be the culprit. I just replaced an Adcom pre-amp (w/o remote) and it never hummed.

Any ideas as to the source of the problem?

Frustrated in Michigan!
If the preamp's power cord has 3 prongs, try a cheater plug.
Can't say this will work, but it did for my amp's transformer hum. Try to find which circuit the pre-amp in question is running off of. Then check the circuit breakers in the service panel. If per chance, your pre-amp's circuit is on the opposing phase of some of your other audio circuits then it is possibe that some AC noise is being generated thats affecting the transformer. If so, then have an electrician move all of your audio circuit breakers in the service panel to the same phase of 110 volts. That cured my amp's transformer hum.

Keep in mind that I've had 5 used amps on this same circuit without any hum. My last amp hummed until I moved the amp's circuit over to the same phase as the others.