I own a Bryston 4B-ST, and have a couple of suggestions for you:
1. Check the switch on the rear panel for the "Bridged/Individual" mode to be sure that you have not accidentally set it to "bridged" (which would cause the amp to operate in only one channel).
2. Check the fuses (under the panel next to the power cord connection).
3. If neither of the two steps above result in a "fix", then send an E-mail to James Tanner at Bryston. Go to Bryston's home page (www.bryston.ca), and at the bottom of the home page there is a link for technical questions. Tanner is terrific about providing fast answers to E-mails he receives.
If your amp does have an actual electrical problem, you can remove the non-functioning amplifier module for the dead channel and send only that module to Bryston for replacement or repair. Bryston will sometimes send you the replacement immediately while the module from your amp is in transit to Bryston's U.S. repair facility (in Vermont, as I recall).
1. Check the switch on the rear panel for the "Bridged/Individual" mode to be sure that you have not accidentally set it to "bridged" (which would cause the amp to operate in only one channel).
2. Check the fuses (under the panel next to the power cord connection).
3. If neither of the two steps above result in a "fix", then send an E-mail to James Tanner at Bryston. Go to Bryston's home page (www.bryston.ca), and at the bottom of the home page there is a link for technical questions. Tanner is terrific about providing fast answers to E-mails he receives.
If your amp does have an actual electrical problem, you can remove the non-functioning amplifier module for the dead channel and send only that module to Bryston for replacement or repair. Bryston will sometimes send you the replacement immediately while the module from your amp is in transit to Bryston's U.S. repair facility (in Vermont, as I recall).