It really depends on age, warranty left, and most importantly functional and cosmetic condition.
I have a '99 B60 R with phono. I had it upgraded to SST by Bryston last year. I have the spec sheet, etc. If I were to list today, I'd probably list it at $1k. Maybe throw in shipping to the ConUs and paypal if I needed to sell it quickly.
I don't have any need nor desire to sell mine though. $850 would be an absolute minimum I'd have in my pocket after everything is said and done.
If your's in in good shape, you're selling yourself short by letting it go for that price IMO. But again, I don't know how quickly you need to get rid of it, where you are, it's condition, etc. At your price, it would probably last an hour or two on Audiogon even if something was wrong with it. A buyer would know Bryston would fix it under warranty.