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!