[rhart]

Hi all. A friend is giving me an old 4B pro that he bought for his studio (1979 he thinks). It's a little rough looking, but he says it works just fine. Anyone have an safety tips on this thing? Any other comments? I'm currently runing a 60B-SST with some PMC DB1s. It'll be interesting to see how the 60B's 60 moderns watts stacks up against 200 vintage watts.

[b5pt9]

I have one of these at home too, currently not is use though.  The power switch contacts welded closed on one channel shortly after I bought it, and I haven't opened it up to replace the switch yet.  Bryston sent me a new switch for $15 I think, or perhaps even free, can't quite remember.  I love Bryston service.

If the amp doesn't have a ground lift switch on the back you may run into ground loop hum.  I DO NOT recommend doing this for safety reasons, but the only way I could get rid of the ground loop hum was using a cheater cord (no ground prong).  The safety concern with using cheater cord is that if the amp has an internal fault the chassis can become energized but the circuit breaker will not trip necessarily.  Anyone who touches the chassis in this condition WILL BE ELECTROCUTED!! 

Another thing is the older rectangle (E-type) transformer makes a fair amount of low level mechanical hum.  This is normal and can only be rectified by changing to the newer toroidal transformers for $$.

Good luck with it, cheers.

[rhart]

Thanks. I don't think I'll be cheating the ground...ouch.

[rhart]

Finally had a chance to hook up the old 4B. I won't write a comprehensive comparison between the 4B and the B60sst, but overall the 4B is impressive. Obviously, there's more power with the 4B (200W vs. 60W), but there's also a slight increase in soundstage depth and width and a bit more perceived air between instruments. The bass is tight and clean. The highs are not as smooth as the B60sst. For a 30 year old amp: neutral and clean. If someone can't afford another model, go with the original 4B.