Tiptop Audio RS909, Drum Module, Analog rimshot sound generator of the TR-909 in Eurorack format, Sound generation: Three T-bridge oscillators, each generating a damped sine wave at a different frequency, are mixed and sent to a VCA - controlled by an envelope generator that delivers the familiar attack-rich sound, The original circuitry has been supplemented with frequency control of two internal oscillators to allow more timbres, Width: 4 TE / HP, Depth: 36 mm, Power requirement: +12 mA (+12 V) / -10 mA (-12 V)