Groupie is a group of enthusiastic fans of any type, in the US.
They referred to them as bands, and their electronics as "Band Amps", "Musical equipment" or "Guitar amps" when I was doing that work in the '70s & '80s. Most repairs were done by part time techs at music stores, but there was usually a shop that specialized in amp repair in bigger cities. I even saw a few british amps, back in the '70s when some clueless wanabes were trying to copy one band or another, right down to the brand of wire and connectors for their cables. The only thing they forgot was to learn how to play music, sing, and perform in front of people who want good music. ;-)
As far as I am concerned, panel mounted controls are the only way to go for any application that involves rugged service. PC mounted are ok for internal adjustment, but nothing beats a mil spec made to last for
25 years of daily use.