Bryston 4b vs. Bryston 4b st.

Is there real difference between these two amps. Price differnence in used market seems to be about $400 to $500. Is it worth that extra cost? Thanks.
The 4B-ST carries the suffix "ST" to recognize the complete re-design of the circuitry done by Stuart Taylor. He completely revised the circuitry in the 4B, using much shorter internal connections, improved parts, significantly larger power supplies, etc. If you are interested in more background about the design of the 4B-ST, visit the Bryston web site and look through their archived newsletters and product reviews.

In short, the 4B-ST offers substantially better audio performance than its predecessor, and is well worth the additional cost.
Sdcampbell is right on.I had both and concur,a noticeable difference on all levels,Bob
Another agreement with Sdcampbell. There is no comaprison, the 4B ST is significantly better.