The gentleman I purchased the amp from was the son of a recording engineer in Florida . He said the amp was powered up annually to maintain the caps, but was never used in the studio or otherwise . What ever was done or not done the amp looks and works like new.
I took the lid off and not a spec of dust, even smelled new. Anyway , I got lucky , mint condition 25 year old 3B-ST. I love it.
Thanks for the replies.