Cool! It's a start just getting the name Barth.
But it says U110... So it's probably something else(unfortunately)
I found this page: BARTH U110 Broadcast-Peakmeter-Amplifiere for all Siens  - €*100.00 : Schmitronic, Studio Equipment
It says that it's a amplifier for a light peakmeter.
Not sure what that is... Is that just an amp to drive an old style vu-meter??
(those with a moving mirror)
It sort of looks like the eq-modules are of another brand, just a slight different
design of the front plate.
I have no idea how the preamp is adjusted on this...
Wonder if it's those knobs below the eq section...?
(haven't had the time to take this thing apart yet)
Anybody have an idea of the gain operation on this one?
Thanks for the info! Let me know if you come across anything else