My 4B-ST runs Hot

Four inches above the amp, open all around. Rack is Lovan. I use Audioquest Lapis ICs and Audioquest Sterling speaker cable--terminated for bi-wire at store. I must add that the heat seems concentrated on the right side of the top lid (if you are looking straight at the amp). The cooling fins on the sides of the amp are always warm, but not uncomfortably hot. However, the sound does not suffer at all, in fact at first I attributed the heat to normal amp life. I always turn my amp off after a listening session, so I don't know about the temperature when the amp is not that active. I don't know if there is something wrong with the amp that will crop up in the future. I wanted to bounce all this off everyone here first before I start shipping it back to Bryston.

My speakers have a 90 dB efficiency, 8 ohms nominal impedance, recommend 110 watts for amp power. The 4B-ST should kick them around the block no problem. The funny thing about all of this--Bryston is the distributer for PMC monitors in the US and Canada. PMC uses Bryston amplifiers when they test their speakers. I thought I was buying the best possible match for my amp. Oh well, I'll just put a bag of ice on the amp and it'll be fine. Just kidding :) I forsee a call to Bryston in my immediate future. Hopefully the amp will not be out of my life for long. By the way, if you all have never heard of PMC speakers, you should check them out. You might find it interesting to know that PMC (Professional Monitor Company) boasts that about 90% of all CDs made are mastered on systems using PMC monitors. Thanks for all the help.

Alright, just a follow up. I put the amp through the paces tonight for about an hour. It stays cool for about two songs (rock, R&B) at a pretty good volume. Then it begins to warm up pretty steadily, favoring the right side of the amp. After about an hour of playing, moderate to loud volume (classical, single vocalist and small assortment of instruments) I checked out the amp. The left side of the amp is merely warm, both the heat sinks and top of the amp are the same temperature. The right side of the amp is too hot to leave a hand on for long. The heat sinks on the right side are scalding also. The heat is present from the front of the amp to the back of the amp on the right side. I did not record the temperature as I do not have a thermometer to check it with, but I figure it was pretty damn hot if I couldn't leave my hand on it. Now, the interesting thing is that when I stop the music, the right side of the amp slowly returns to the same warm state the left side of the amp is at. I plan on calling Bryston soon.

Nope, my speaker cables and interconnects are hooked up correctly. The only other thing that might be causing this is my pre-amp. For anyone who owns a Conrad-Johnson product, you know that they are not phase inverting. This means that when I send the signal out from the amp to the speakers, the red terminal on the Bryston must correspond to the black terminal on the speaker. But even if I hooked that up wrong, which I did not, I still don't see how that could hurt the amp. Phase inversion really just affects the speaker, I think. Anyone else out there who owns a CJ product want to chime in?

Just got a response from Bryston. They want me to see if I can duplicate the problem after I switch my speakers around. Guess they want to rule out a bad speaker or cable. I'm going to try it again, but I've moved my system to different rooms in my house often enough to have switched the speakers around several times. This heat thing has pretty much been a feature of the amp since I got it. Oh well, I'll keep everyone posted on what happens.

Well, switching speakers or cables around did nothing to diminish the heat problem. The unit is going back to Bryston tomorrow. Hopefully the excessive heat did not damage the internal components.