Audio Systems: Stereo Amplifer, quad 66, quiet channel

Question
Sir I have Quad 66 Pre and 606 Power Amp. I just want to know about the balancing part of the Quad 66 Pre Amp. When balancing from centre to left or right  channel then oposite channel has very low sound. But Sir in my conception when balancing from centre to left or right  channel then oposite channel has nil ( Zero ) sound. My question is my Quad 66 Pre amp is that nature of balancing or in my Quad 66 Pre Amp has any problem in balancing part, that's why when I balancing from centre to left or right  channel then oposite channel has very low sound.

Answer
This is very easy to check.

Just turn the set off.  Then reverse the cables between the output of the pre and input of the power amp.  Then when you turn it back on try the balance check again.  If the same channel remains the quiet one you have a bad power amp channel. If the quiet channel switches to the other side the pre is defective and needs service.

Best wishes.

PS: In rare cases it can be the audio cables, too!