[gelmhirst]

I have nothing out of my left speaker. All preamp sources feed the right speaker successfully. I've switched the cables from right to left, nothing again from left. I've switched to a spare speaker, spare ICs, and spare cable, nothing.....   My fear is that the left channel of the amp is the problem.

Bryston 3BST and BP5 pre

[jethro]

Your right channel (from preamp to speaker) works so If you switch the right speaker cable to the left speaker and get no sound then it should be a problem with the left speaker and not the amp. On the other hand, since you used a spare speaker, it almost sounds as if both the left speaker and left amp channel have problems. I' would repeat your tests, but don't use the spare speaker, unless you are sure that the spare works. Also if you are bi-wiring or bi-amping I would go to a single wire setup. I had a speaker that wouldn't work at all when bi-amped but worked fine when single-amped. Good luck.