The ADL Opus 3 Discrete Optical Compressor/Limiter is a close cousin to their world-famous ADL vacuum tube 1000. It is an all discrete solid-state design commonly referred to as a fixed gain circuit.
 
It's features are:
 
Transformer in/out
90 Hz Hi-Pass Filter Switch
Bypass Switch
Heavy-Duty Chassis
Handcrafted in the USA