Modulation is the core concept of modular synthesis: parameters changing over time, adding movement and musical interest to what would otherwise be merely static sounds. Being able to control the amplitude of signals throughout a patch is therefore essential, and one can never have too many voltage controlled amplifiers (VCAs).

Designed as a fully-featured modulation hub for Eurorack synthesisers, Morph 4 takes the basic concept of the multi-VCA module to the next level.

Four linear amplitude modulators are controlled by a master ‘morph’ parameter. The response of each modulator to this parameter is completely variable, both manually and under voltage control, and can be overridden if desired. Each response is triangular, with the ‘position’ parameter setting the maximum point along the morph axis, while ‘span’ determines the width of the triangle’s base.

In addition to separate signal inputs and outputs, a variety of combined outputs is available as well: A+B, C+D, add (unity gain) and averaging mixes, and instantaneous minimum and maximum. Input normalisation makes it easy to send the same signal to multiple modulators, while output and modulator response LEDs provide essential visual feedback.

The combination of master control, fully flexible modulators and multiple combined outputs creates a module truly embodying the spirit of ‘patch programmable’ modular synthesis. Use Morph 4 as a voltage controlled mixer, dual crossfader, dual panner, interpolating scanner, interpolating distributor, quad VCA, quadraphonic controller, slope modifier, rectifier, complex waveshaper or something in between any of those—the choice is yours.