The Amp Quits Agin -- Am I Missing Something?


I have a 4b-ST I left on for about 4 hours Friday night only to return to find that one of the channels had died in my absence. While I was gone, the system was on, but not being used. I haven't really investigated at all to guess what may be wrong, other than to determine that that CD player and the preamp are still working fine. The left channel on the Bryston seems to be working fine, as does my left speaker. The right channel, however, appears to be completely dead (even the left LED is dead) and I have no idea what may or may not have happened to my left speaker. I'd love to not have to send the amp back to the shop (again, it was there in February for a muting switch) and am hoping that I might have missed something obvious. Any thouhgts? Thanks.
mezmo
Yep, I'm an idiot. Fuses external. One fuse blown. Time from diagnosis of problem to cure, approximately 15 seconds. Time spent discussing and wondering about problem, 5 days. Oh well.
Ok, color me frustrated, but how do you get the stinkin' lid off of the thing to check the fuses in the first place? I've got star wrenches, allen wrenches, screw drivers of every stripe, not to mention a whole array of other assorted implements, and Bryston has to come up with yet another means of performing the simple task of screwing a lid on. Anyone know the name and size of this the latest single-use piece of equipment I need to find?
If a check of the fuses yields nothing, then I would try swapping the input leads from the preamp between channels, to make sure it's not an upstream problem. I would also swap your speaker leads to make sure the speaker on the dead channel didn't suffer damage, or that the speaker itself is not the problem. Good luck!
Sounds like a plan. Many thanks. The thing's not set to bridged (yes, it was the first thing I checked, all the while asking myself how, sitting in a room by itself, it could have switched itself to bridged but checking it none the less). I'll have to have a gander at those fuses when I get home. I've corresponded with James Tanner before and there's no doubt about it, he's one of the good ones.
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).
on the plus side, you couldn't ask for better service than you'll get from bryston if something is wrong. my former amp was a 4b and it did indeed have a problem. shipped and fixed in a jiffy, and all i had to pay was one way shipping to vermont.
Ugh, as I suspected. My hope is that the channels are on independant fuses and that one of them went on me -- here's to hoping for the simple solution. Haven't checked them yet, but that's going to be the first (and likely the last) place I look when I start digging. And to add insult to injury, I just had $200 in new CDs delivered about 5 minutes ago. Darn lousey timing. (PS as for my apparent inability to tell my right from my left in the original post, what can I say? We'll keep it simple: on side work, other side no work).
Whatever it is, it doesn't seem like an external enemy -- otherwise both amp channels would be on hols. EXCEPT if the main ground is wired onto the right channel & it blew due to trash entering the system from the mains while you were away. I hope Jc has it right, otherwise you may have an output transistor that's kicked the bucket.
Not very helpful -- we need Sean & Co here. Keep a stiff upper lip!
Doesn't sound like anything obvious. Have you checked to see if any fuses have blown. Sometimes there will be some inside the amp for each channel. I'm not sure regarding this particular amp. That is where I would start though. If all ok there I think it is time to call Bryston. Hopefully it will be a fuse though. I have had similar situations which 9-10 times was a fuse I overlooked. Good luck