The unit features a gain-reduction element, positioned immediately after the input transformer. It is controlled by the sidechain amplifier, which also contain the two time control circuits - one for fixed and one for variable Attack/Release. The two time-controllers can either be used separately or combined. This circuit contains semiconductor OP-amps for the entire control.A dedicated Bus selector with three positions (Off, Bus 1, Bus 2) is used whenever you want to link several compressors together.
The gain-reduction element is followed by a tube-based push-pull amplifier with variable gain up to 30 dB. Input and output transformers have a static-screen between the primary and secondary wirings. Both Input and Output are balanced as well as fully floating.
Opto Compressors CL 1A and CL 1B difference:
The circuit and functions are exactly the same. The amplifier section in the CL 1A is hardwired. In the CL 1B the transformers and the tubes are placed inside the unit on a printed circuit board. The control circuit is on a PCB in both units.