1. Make sure the imbalance occurs with the preamp set to MONO and that the balance control on the preamp is centered (10 click stops from either end of rotation) to assure that both preamp line channels and both amp channnels are getting the identical signal. If this "cures" the problem then the imbalance is being caused by a switch dropout in the preamp or with the source used. If not, then proceed as follows.
2. Physically swap the speakers in the room left to right. Physically disconnect each speaker from the speaker wires, move each to the opposite locations, and connect them again. Don't move the speaker wires. Does the imbalance follow the speaker? If so it is the speaker.
3.If the imbalance does not follow the speaker then return the speakers to their original locations. Now reverse the speaker wire connections, left channel to right channel, at the back of the amplifier. If the imbalance follows the speaker wire, then the problem is with the speaker wire, or ahead of the speaker wire. If the imbalance does not change, then the problem is room acoustics.
4. Now swap the other ends of the speaker wire from speaker to speaker. If the imbalance does not change, then the speaker wire is eliminated from being the cause (the imbalance did not change no matter which channel the speaker wire was connected to). If the imbalance changes channels, the problem is a defective speaker wire or ahead of the speaker wire.
5. Now put everthing back to normal. Now reverse the connections from the preamp to the amplifier just at the amplifier end. If the imbalance does not change, then the preamp and everything ahead of the preamp is eliminated as a possible suspect. If the imbalance does change, then reverse the connectins at the preamp end too. If the imbalance changes, then the most likely suspect is the line section of the preamp, or a possible defective interconnect cable. Replace the interconnect cable set. If the problem does not change after replacing the interconnect cable set, then the preamp line stage is defective.
6. If the imbalance did not change in step 4 then the speaker wire is eliminted and also did not change in step 5, the problem must be a defective power amp channel.
7. The easiest way to follow all this is to draw a block diagram of each step on sheets of paper and eliminate suspects as you go.
Simple, no?
Yah, I know its a lot more fun to just install a $500 AC power cord and another thousand worth of Black Gate capacitors, but unfortunately that won't get to the bottom of the problem
Frank Van Alstine
