bryston ST and NRB question

If you want to save some money on the phone, go to Bryston's web site at: www.bryston.ca

If you scroll to the last line of text on the home page, you will find the following link:
"To receive answers to Technical Questions please click here."

Click on that link, and you will get an E-mail form address to James Tanner, the technical guru at Bryston. Tanner is very prompt about responding to questions (usually within a few hours).

I recieved a later 3B ST THX (not SST, final checkout 2003/02/07) on a warranty issue (Thank you Bryston) which replaced my 3B NRB. If memory serves me correct I heard an early 3B ST after purchasing a new 3B NRB in 94 and only perceived a small difference, not enough to justify the upgrade path Bryston offered at that time.
But my current 3B ST THX is an altogether different beast, the audio spectrum seems extended in both directions with a lot more ambience and detail while remaining very smooth This unit is very good, prior to receiving the 3B ST THX I was looking into replacing my current audio system Celestion SL6S+’s), Teac VRDS20, Bryston .5, Rega Planar/Blue Point, but the new 3B ST has made my system (music) sound better than it ever has before, even compared to current systems I have auditioned.
Very often Bryston quietly implement revisions on current units, this ST has later input (Rev 5.3)and output (Rev 5.2)boards and an updated Main Power Board (PWR-MB6), In other words a later ST have a number of revisions over an early ST (better input/output boards) even the top plate is different.
So to answer Krazeeyk’s question Bryston made a few changes on the ST to NRB which are documented on many sites. What one does not read about are revisions within a current line up. An early ST sounded better than the NRB but a latter ST sounds a lot better if not completely different, probably closer to the current 3B SST.
Hope this helps

its a little late but this info fits your question exactly but not totally:
the differences between the NRB and the first ST are partly available in the NRB when using the balanced inputs. The exact explaination is available in the Bryston published "critical acclaim" in the amp section [vol 5 page 86] the article from[and obviously available from] October 1996 vol.19 no.10 "Stereophile" in the outake titled "the Bryston ST's" quote "it was evident to Taylor that the NRB series' balanced inputs sounded better than the unbalanced..." this difference Bryston calls their proprietary input buffer, I don't know what it is but its in the NRB,s balanced inputs only, whereas in the ST all inputs have it. BTW, the NRB can be factory upgraded to full ST , but not unfortunately to SST [however i think a ST can be upgraded to a SST] A very interesting subject that was mentioned above remains beyond my ability to obtain, that is a cronology of the upgrades/changes the Bryston line has received, in the case of the 2B 3B and 4B, since 1977. i shall post this very question.

Vettemanbc - for the record a ST version cannot be upgraded to the SST version. Too many changes according to James Tanner.