Custom GSSL Mastering Compressor Build

This was born of a client's request to have a mastering version of an SSL/VCA based bus compressor.

We started with the basic GSSL circuit and threw in a bunch of 'standard' add-ons courtesy of Expat Audio: Turbo mod, VU meter driver, filter board, and 'Cavendish' board using QuadEight style discrete op amps for input and output.

Then we added the custom extras.

Stepped threshold and output controls with the Threshold being a 24 position switch; a 1.5:1 ratio option was added; all resistors are Dale CMF 1% and 0.1% tolerance for tight channel matching; we used THAT "A" grade VCA's in the signal path for the lowest distortion; a vintage style Sifam meter; high quality WIMA and Nichicon low impedance capacitors; and then my favourite part- multiple output drive options.

We installed 3 output choices- a more modern API style transformer, a rounder Urei option similar to the LA2A output transformers, and a super clean BurrBrown balanced line driver. A rotary switch selects the output option.

The whole project was finished off with a custom faceplate and bakelite knobs from Davies Molding. Amazing sounding unit and the client was thrilled with how it came out.