Tony, Just a thought, try disconnecting the ics from the Power Amp's inputs. Power up the Amp just by itself, with just the speakers connected to it. If the Amp still makes the noise, "push/pull effect", through the speakers then that would indicate the problem is with the Amp.
What is the make and model of the preamp? Does it have a mute switch?
What is the make and model of the SS Amp?
What is the make and model of the preamp? Does it have a mute switch?
What is the make and model of the SS Amp?