"There is an authorized service shop for Blue Circle."
That would be-
https://www.dtsaudioelectronics.com/Authorized-Service.html
Blue Circle Gear?
I'm considering a used BC 21.1 preamp. I've never owned a Blue Circle piece. Since they're no longer in business, what are your general thoughts on their gear in general as far as build quality, reliability and sonics? And any particular thoughts on their preamps in particular, esp. the BC 21.1?