Faithfully reproduces the circuit of the [modular 55 & 35] series, with 4 switches, it is possible to send cv signals to multiple oscillators external input jack equipped with a dedicated attenuator 3 for frequency control of the vco module equipped with two switch and summation cv inputs three parallel cv outputs can drive multiple 921a/b oscillator modules eurorack specs: 8hp, 5ma +12v, 5ma -12v.