3U Synthesizer Modules

This section contains modules that can be used to modify the frequency spectrum of incoming waveforms under voltage control, to modify the overall distribution of fundamental or harmonic components or to emphasize or remove specific frequency bands.

GMS-294AEU 4 Pole Low Pass Filter

A transistor ladder made with vintage transistors gives the same sonic character to the GMS-294A Four Pole Low Pass filter recreation that the original 904A Four Pole Low Pass filter possesses.

PMRESO-EU PM Resonator-3 Channel Formant Filter

The PM Resonatorâ„¢ is a recreation of the formant filter section of a Polymoogâ„¢ synthesizer in an 18HP modular panel for Eurorack (EU) format synths. 

GMS-214EU Multimode Filter

This multimode filter allows selection of one of fourteen possible filter configurations from front panel switches.


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.


Grove Audio builds microphones, preamplifiers, equalizers, compressors and other professional audio equipment for performance and studio use. We build units in popular formats such as 19 inch rack mount and 500 series 3U modules. We can also produce custom designs on request. Contact us for a consultation.


You can explore all of our products, download spec sheets, and purchase our products in the Grove Audio Synth Store. You can also learn about our periodic specials and new product introductions. Click the button below to go directly to the store.

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