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.
You should be able to set your balance control so that the central image, usually the vocal, is right in the middle of your soundstage.  If you can't do that there is a problem with your balance control. 

You don't say how loudly the L or R channel plays when you have the balance control set all the way to the other channel.  If  it's more than minimal volume, that would indicate a problem with the balance control also.

You can call Cambridge Audio Customer Support at :   (877) 357-8204
Thanks for taking the time. When the balance is all the way to the left channel it is definately louder than the right and vice versa, but doesn’t silence the opposite side as it should.
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Thank you Elizabeth I'll look into that more. Appreciate it!
This is how most balance controls work.

Since usually balance is only off a few dB, you don't want a very wide range balance control. Something that adjusts maybe +- 6 dB to +- 12 dB is more than ever gets used. This lets you adjust with finer control.

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Over all the preamps and integrateds I've owen, they always muted the other channel when the balance was at full turn to the other channel. Something's not right there. Could be the value of the balance pot is incorrect.
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Thanks for everyone's input. Going to get it looked at by my dealer in town. The balance knob is shared with the volume knob, after selecting volume or balance in the menu.