Mystic Circuits

3DVCA is a quad Voltage Controlled Amplifier, Mixer, and Axis generator combo. Designed to be a highly customizable connection matrix, 3DVCA packs a boat load of utility into a small 6HP package. Four VCAs share the three macro controls: X, Y, and Z. As a group, they shape incoming or outgoing signals and emulate the coordinates of a point in 3 dimensional space. These controls allow the VCAs to work together in mono, stereo, or quad and accomplish a variety of mixing, crossfading, or panning functions. For easy integration with multiple 3DVCAs or other mixer modules, each VCA output has a dedicated sum input. This allows an entire mix to be automatically passed along to the next mixer in the chain.

3DVCA is designed to be used in the following functions:

  •  Quad monophonic crossfader
  •  Dual stereo crossfader
  •  Stereo balancer
  •  Stereo VCA
  •  Mono to stereo panner
  •  Unity mixer with up to eight inputs
  •  Quadraphonic panner

Each output has a dedicated SUM input which allows an external signal to be automatically mixed into the output signal. This allows 3DVCA to daisy chain both with other mixers and other 3DVCAs. For example, you can create a full mono, stereo, or quadraphonic mix by plugging the output of each 3DVCA into the sum inputs of the next 3DVCA in the chain. Using this method, a set of 3DVCAs can create a fully voltage controlled and decentralized mixer which ties together anything from a small skiff to a monster synth.

When 3DVCA works as a crossfader or panner, the and parameters follow an equal-power curve that keep output signals at the same volume no matter how many inputs are mixed together. This is in contrast to the Z parameter which follows a linear curve to always behave predictably with external modulation sources. All inputs are fully DC coupled in order to work with modulation speed signals as well as static DC voltage sequences; this means that 3DVCA can handle any sort of signal that you throw at it. All op amps in the device employ rail-to-rail inputs and outputs to enable the largest headroom when mixing many different signals together.

Each module is built with high quality components, Sound Semiconductor VCAs, and rail-to-rail OPA family op amps for maximum headroom. On top of that, each VCA is fully DC coupled to work predictably with any type of signal you throw at it. 3DVCA has the potential to take your Eurorack modular to a whole new dimension of sonic exploration.



30mm Depth

45mA @+12v

45mA @ -12v