Hi Smerles,
I've reconnected the 3BST a number of times just to check on each configuration and now have it reinstalled, no noise from the the speakers it's dead quiet with my ear to the drivers.
Interconnects I checked and swapped over and over, ran current from different outlets and cut the breakers for every socket just to be sure.
After connecting the 4B I checked all the outlets for polarity and grounding, some were actually incorrectly wired, which I corrected but never affected the 3BST as they were. Tried lifting the grounds, still to no avail. I've also have headphone amps and a number of high end headphones which never showed up any grounding problems.
As I mentioned yesterday, I made the discovery (which escaped at the beginning) that by disconnecting one interconnect from the 4B even when everything is connected and powered up the system was dead quite.I reversed the procedure for the other channel, same results.
Logic leaves me to believe that there must be a grounding problem between the dual mono configuration of this 4B, I spent over 20 years doing Electro-acoustic music production and sometimes dealt with hundreds of cables, which of course became a nightmare in tracking down a ground loop so this simple set up has me scratching my head, (ok, pulling out my hair).
Bottom line is, with the 3B installed in the exact configuration there is no hum-buzz, just silence, that is until I hit the play button.
With the 4B the noise from the speakers is audible from the listening position or anywhere in the room.
I should also mention that the reverse is true for the mechanical noise, the 3BST is much louder than the 4BSST which for an amp that size is almost dead quiet even with your ear to the chassis.
"I wonder if switching the amp has just brought to the forefront a problem you had before."
I've given this aspect a serious consideration and hope this is not the case as it would entail redoing the wiring (not practical as I'm currently renting, sold the house) or investing in something like a Torus which could get a bit pricing for a problem that did not surface before.
So I've gone ahead and boxed up the 4B to send to Bryston, if the unit is 100% then I'll will probably resell it, tryout a 3BSST (with my fingers crossed) or keep it in storage till I relocate, but I must say that I really appreciate the help from Bryston and the feedback in trying to solve this problem. Even with the noise problem I'm still able to hear the improvements Bryston implicated in the SST series and would be sad to see it go.
If Bryston do ascertain that there is indeed a problem with the unit I'll be happy and be able to just sit back and enjoy the music, that is after I pickup my BCD-1 next month though.
Robert