What is my power conditioner up to?

I have recently purchased a PS Audio Quintet. I like the effect on everything but my solid state mono amps. While it seems to increase detail and enhance the soundstage, I notice that the bass fullness has decreased especially at lower volumes. It kind of reminds be of the old loudness switch on older receivers. Without the conditioner it sounds like the loudness switch is on. With the conditioner it sounds much less full in the bass like the loudness switch is off. What could cause this effect? I have the amps plugged into the power amp sockets so I assume I am getting enough current. It just sounds thin at low volumes. What gives?