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.

Argent, I have used Bryston 48's and 7b's for years with low impedence Magneplanars, Thiels, and Apogees and have never experienced any excessive heat problems. I will say that the Brystons run hotter with Apogee Caliper signatures than with the Thiels or Maggies, but never so hot that you can't put your hand directly on them. I would advise getting a calibrated cooking thermometer and measure the heat at several points on the top and sides of the amp...then call Bryston with your temperature measurements and a description of your components, and see if they think it is running too hot.

Argent,
I'm not familiar with the speakers that you have, but, if they aren't very sensitive or dip into the low ohm range (1-3 ohm) they can make your amp run pretty hot. Especially if you like to listen to your music quite loud. I used to have a pair of Infinity Kappa 8's and they would dip into the 1 ohm range (with sensitivity at about 84-86db)and would make my amp run VERY hot, could even cause the amp to activate it's protection circuitry if we really cranked it up. And this amp had plenty of arse. I now have a pair of Legacy Focus that are sensitive speakers (95-96db and operate @ 4 OHM) and don't have this problem. My amp rarley even gets warm. That Bryston has tons of arse, so either your speakers are the cause, as mine were, or the problem is elsewhere. Maybe someone else has another suggestion. Don't know if this helps. Good luck.

Joysjane,
I have the Legacy Convergence, which were rated by Legacy as having the same sensitivity as the Focus. Audio magazine reviewed the Convergence and measured their sensitivity at 92db. Legacy seems to include room gain in their figures. I still love em !! (the speakers). My OCM 500 amplifier runs around 115 degrees with these speakers. At 130 degrees things become to hot to hold your hand on.

You mentioned that the amp seemed hotter on the right side of the top. The 4B-ST is a symmetrical construction, with the heat sink modules each containing a separate channel of amplification, with the twin toroid amps occupying the center of the chassis. The only other factor I can think of that might cause excessive heat on one side (given the symmetrical internal layout) is a badly adjusted DC offset. I think your problem merits a call to Bryston, since excessive heat will decrease the life of the solid state parts and output transistors.