Hum coming through speakers via Bat 300X

I just purchased a used Bat 300X/se and a new pair of Thiel CS2.4se's for a second system. Set them up last night and have a pretty good hum coming through the speakers. As I turn the volume up with no source playing the hum gets louder. Another weird thing is that I have to turn the volume up a lot more when the CD is the source compared to the turntable. I have the Bat plugged into a PS Audio P5 Power Plant which has never created a hum before when I used it. Any thoughts on either issue. Thanks-------

Problem solved! It was the CDP, installed cheater plug----dead quiet. All is right with the world again, almost. Thanks again everyone.
Your amp has a Volume Offset feature that lets you adjust the levels of each input individually so they have the same subjective playback volume at a given volume setting. Check your manual, it's a great feature and a great amp. I love mine.