The 4Bsst/2 has a really low noise floor. And like the reviewer said you would swear that it wasnt a Bryston when compared to even an sst. I ownd both 4b's the sst and sst/2.
If you want even more power with more clarity and less noise try the 14B. They are indentical in tone but the choke filtering tied in with almost double the power, it easily makes its worth twice the price. The 14B seems to drives the sense of air and it becomes part of what we hear and don't hear. Air around the instruments becomes part of the sound stage and you just don't get that with the 4B. At 4k the 4B is still an extremely good value imo. The amp is so versatile and will drive any speaker load at any volume. The phone jack access in the back with xlr makes it great for pa or bass systems. Its just an all around versatile amp that makes it a great bargain.