With the Model 110 Quad Gate, musicians can add the distinctive sounding, nonlinear VCAs of the Buchla 100 series to their Eurorack synthesizers. The circuits are controlled via potentiometers and CV inputs. The VCAs' response characteristic is exponential in the first third of their control range. In the second third, the response characteristic changes to linear and finally to logarithmic behaviour. Additionally, some saturation is applied at the upper edge of the control range. The Model 110 Quad Gate does not feature vactrols. Thanks to its ultrafast response time, the module is a great partner for creating percussive sounds. Furthermore, the Model 110 is able to perform amplitude modulation at audio rates.
The Model 156 Control Voltage Processor was developed as a "front end" for the dual oscillator of Buchla's 100 series. The module is composed of two circuits, which can mix, attenuate, offset and invert signals. Catalyst Audio's Model 156 M transfers the classic Buchla concept to the Eurorack world. Thanks to its overhauled design, the Model 156 M is fully compatible with the 1v/octave standard. An exact clone of Buchla's Control Voltage Processor is available under the name Model 156 V.