Full featured, fully modular synthesiser for Eurorack with a pre-patched normalised signal path for quick setup.

A combination of the XVCO TWO, Raging Bull 3.0 VCF/VCA, and System X Envelope, where each section can be used completely individually or as part of the larger whole.


For this item we offer a CHIPSET which contains the following:

For all other components required, please see the build document.


Product is a full featured modular synthesiser. You can use it without patching, or you can use it as the heart of your modular system, or you can use each section individually. Each section is fully modular, but also features pre-patched normalised signal paths for fast set up of new and exciting sounds.

Product is a combination of three individual Frequency Central modules:


  • onboard LFO for PWM and FM
  • onboard noise source

Product features a motherboard on which all pots, switches and sockets are mounted, this is also where the pre-patched normalising happens. All pre-patched connections can be broken simply by inserting a jack into the relevant socket.

The pre-patched normalising is as follows:

  • The onboard LFO is available for both FM and PWM of the VCO.
  • The three VCO waveforms are available at the three VCF signal inputs.
  • 1V/oct input, LFO and ADSR are available at the three VCF signal inputs.
  • The VCA can be operated by either ADSR or gate input, alternatively it can be set to drone position.

For DIY’ers:

To simplify the build process, there are three daughterboards that plug into the Product motherboard: VCO daughterboard, VCF/VCA daughterboard, and ADSR/noise daughterboard. First you can build and calibrate the VCO daughterboard, plug it into the Product motherboard, get it running and have some fun with it. Then build the VCF/VCA daughterboard, and add it to you expanding modular synthesiser. Finally build the ADSR/noise daughterboard, and your synth is complete.

Product Specifications





12V draw


-12V draw


5V draw