WSY-104EU FM/PM Operator

Thru-zero FM & PM VCO for Eurorack

The WSY-104 FM PM Operator module is a through-zero digital oscillator that has FM and PM modulation capability. The default output waveform is a sine wave although there is a provision for sampling an external waveform and then applying FM or PM modulation. The oscillator also has a feedback control and CV imput for controlling the amount of the oscillator output that will be fed back to the modulation input. The effect of this is to add additional harmonics to the output waveform. A synch input and output are provided to allow the oscillator to be synchronized with an external oscillator input and to a provide synchronization signal to other oscillators.


  • Operation Manual
  • Datasheet
  • ModularGrid

Technical Specifications

Frequency range
1.0 Hz - 22 kHz

Frequency control input
1 V/Octave

FM modulation input
+-5 V

Phase modulation input
+-5 V



We produce electronic synthesizer modules in the two most popular formats, MU (Moog compatible 5U) and EU (Eurorack compatible 3U). A wide range of voltage controlled modules including oscillators, amplifiers, mixers, envelope generators, special effects units, wave generators, filters, power systems and cases allow users complete freedom to configure any desired electronic music instrument.


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Grove Audio has been manufacturing professional recording and modularized electronics for musicians and performers since 1995.