Balance issues?

Hey all. I'm having this issue when I adjust the balance control on my Cambridge Audio Azur 740a all the way to either the left or the right, I am still getting signal out of both channels. I have checked my wiring a thousand times. 
When I hook up a different pair of speakers, same issue. When I reverse the wiring, same issue.
When I switch to my other older amp, balance works as it should. 
Is it possible there is a problem with the azur 740a?
When balance is at zero it sounds ok, maybe even in the middle. But I can't help but think it sounds under performed. I should mention I bought this amp used.
Thanks