Who and what are BEL/Bell Labs amplifiers


I have noted several times the existence of a company called BEL or BELL Labs and their amps seem to be geared towards the high end market, and yet, I cannot find any sort of information about them, just the fact that they sometimes appear in the used market. What sort of company is or was BEL/BELL and what is the typical sound and look of their units. Are they simply a relic or are they just some very well kept secret. Is there are website with detail description of them?
bemopti123
I have a pair of BEL MK V's that were tuned to each other as monoblocs by the late Mr. Brown.  I will keep these in my system until either they or I die, whichever comes first! They are the best sounding most balanced amps I've heard (been in this hobby for 25 years).
@mesch  I own a BEL1001 MK V made in 2007. It is the most prized component in my system. I found it used at a dealership in Chicago. Should (when) it needs servicing I am not sure where I will take it, however will look into it.
We have parts to repair the BEL amplifiers.
Brooks Berdan Ltd.
www.brooksberdanltd.com
626-359-9131
Monrovia Ca.
I just purchased a v3. Anybody know what the vintage of a v3 would be?  It works fine, but I'm wondering about replacing the caps at some point.  Thanks, Peter