[ancient hippy]

i own 4b manufacture date 11/20/1992. cant see any difference between my 4b and the 4b nrb other than the face plate. can someone please enlighten me

[Ron D]

I think there were a couple of changes but if memory serves me right one the most significant is that the NRB amp employed torodial power suppliers and the prior versions had the typical "block style" wound transformers (forgive my lack of knowledge and poor technical description)...

[ancient hippy]

agreed the toroidal transformers were the biggest difference  however my 4b has 2 doughnut shaped (toroidal)  transformers. what im wondering is if after a certain manufacture date all 4bs had the same internal electronics as the 4b nrb

[ancient hippy]

well my 4b blew a channel so its off to bryston for a warrantied repair. talked to mike pickett and was told that m4b is indeed a nrb and that there are models out there with the older faceplate that are nrbs. perhaps the easiest way to find out if your 4b is an nrb is to weigh it. i believe the origional weighed 50lbs and the nrb weighed 42

[rob80b]

Besides the toroidal transformers and better deigned boards etc, FYI, the balanced inputs, if you use them, supposedly was the start of the ST series "it was evident to Taylor that the NRB series' balanced inputs sounded better than the unbalanced...".

Robert