I agree with Drdiamond, Rsbeck & Tombowlus: my experience w/ power conditioners is virtually identical.
IMHO, in general, a power conditioner is the worst thing one can put into one's system esp. for the pre & the amps. The most benefit I have seen is to create dedicated outlets using dedicated wiring from the mains box (in one's basement/garage, etc). A power conditioner creates far too much filtering that encroaches into the audio band & makes for some pretty lousy listening. Most power conditioners are far too coloured thus impose their signature onto the music.
I use Richard Gray's 400S only on the CDP & TT & never did think of putting the pre & amps thru it even though a communication w/ Richard Gray re-assured me that the 400S did not contrict current. Here I'm using the 400S mainly as a surge protector for equipment that is more delicate than a pre & amp.
Those who listen w/ their pre & amps plugged into a power conditioner are undoubtably listening to music w/ some colouration. This is a fact. They might like colouration & that's just fine but it's still a colouration.
Putting an expensive power cord into a wall outlet that is carrying cruddy power is another myth. We went thru this heated discussion during Christmas break (in that us vs. Corona power cord thread). For this matter, as Slappy said, if you got cruddy power, you are covered in sh**, you can wear a tuxedo to cover it up, but you're still covered!
Get some dedicated lines & ditch that power conditioner!