Non linear analog VCA.
A single rail power supply and all transistor signal path create a VCA with character. Response is roughly exponential in the rst 1/3 of its range, approximately linear over the middle 1/3, and increasingly logarithmic as it begins to saturate at the upper edge of it’s range. No vactrols are used in the 100 series gates allowing for an extremely fast response time and the ability to perform audio rate amplitude modulation.
Catalyst Model 100 modules are as technically accurate reproductions as is possible of the legendary Buchla 100 system from the 60´s. A/B tested with the original 100 series system from the San Francisco Tape Music Center (Now located at Mills College, Oakland).