Hi folks. I have a Yamaha RX-596 2 channel receiver. I have two pairs of speakers hooked up. The front pair is going through a sub (high level input/output). On occasion, the volume on the left channel will suddenly get low. So low that I really have to turn up the receiver to even hear it at all. Today it happened, and when it did I switched the input selector to tuner & VCR. Still no volume. I even tried the pure direct switch, still no volume. I turned the pure direct off and switched the selector knob to "CD" and the volume came back. By the way, when speaker A went out, I checked speaker B (on my second set of speakers) and the left speaker was out on B as well. What do you guys think?