Conceptually, a low-pass gate made in the 1950s would have consisted of a cathode follower, two linear optocouplers featuring incandescent lamps and some capacitators as well as resistors. – A fairly simple circuit design, yet it was never done. With the RK5, Eric Barbour now closes this gap. The module comes equipped with two low-pass gates. Each channel features an audio input, a control voltage input and an audio output. The dual triode, type 17JK8, is a NOS leftover. Back in the day, it was mainly used for building FM radios. In terms of optocouplers, Mr. Barbour deviates slightly from the ideal of the 1950s: Instead of components with incandescent lamps, he uses linear, LED-based Silonex optocouplers. – A good decision, as miniature lightbulbs have a much shorter live span than light-emitting diodes. Due to dissimilarities of the two triodes contained in the tube and rather high tolerance values of the optocouplers, the RK5’s low-pass gates vary in sound. The results from module to module slightly differ as well, meaning each RK5 is a unique piece of gear.
3U Eurorack module, 8 HP wide
Power consumption: 100 mA at +12 V and 2 mA at -12 V. - Attention! While heating up, the module needs about 200 mA at +12 V