Sample and Hold

The Sample and Hold is a straightforward yet versatile module in the Eurorack format. It contains a precision analog sample and hold, a full wave rectifier and a white noise source.

A sample and hold receives a signal at its input, but will not output a signal until it receives a trigger at the gate input. The output signal is equal to the value of the input voltage the moment a trigger is received at the gate input. This output voltage is held until another trigger is received at the gate input. This turns continuous/smooth waveforms into stepped waveforms.

What is unique about this sample and hold is that it was specifically designed to process sensitive signals. Ideally, a sample and hold can indefinitely hold its output voltage. In reality analog sample and holds suffer from “droop,” which results in the output voltage gradually falling as it being is held. This results in tuning issues while using a sample and hold to process control voltage from a pitch sequencer.

This sample and hold was specifically designed to minimize “droop” and can hold voltages for about 10 minutes with virtually no droop. This makes it a great tool for processing pitch sequences and extracting new melodic patterns to be distributed among several different synth voices.


ADA is a patch programmable 3-bit quantizer. ADA’s function is determined by its relationship with surrounding modules. Some uses include, but are not limited to: CV/gate sequencing, staircase generation, bit crushing, wave folding, PWM, and crude voltage controlled amplification. The integrated analog sample and hold allows control voltage patterns to be extracted from the main output and can be externally clocked at audio rate for analog downsampling effects.

The reference level establishes eight equally spaced reference voltages, descending from the panel setting to 0V. As the input signal crosses each reference voltage, ADA counts from 0 to 7 in binary. This binary segment is displayed by the three LEDs and is used to address a bank of eight variable voltages. This constructs the output waveform, which is a stepped version of the input signal. This signal is normalled to the sample and hold input, which can be clocked by the bits from the binary segment, via the panel switches, or by an external gate.

Stereo Interface

The Stereo Interface is a cost effective solution for bridging modular and non modular environments.

The Stereo Interface features two unbalanced mono input channels and two unbalanced mono output channels. The input channels provide up to 55dB of gain, amplifying line level signals to the nominal Eurorack level, while the output channels provide up to 20dB of attenuation, bringing Eurorack signals down to line level. All channels are equipped with sweepable high pass filters and a switchable gain range. The input channels offer a logic section, which provide a gate when the input signal crosses a threshold of 4V.

The Stereo Interface is contained in a 10hp package and is great for stereo/multichannel processing as well as establishing send/return paths from your modular system.

Arturia MiniBrute Modification

This modificiation expands the Arturia Minibrute’s internal modulation matrix and provides buffered outputs that allow internal control voltages to interface with external modular synthesizers.

These modifications were able to be executed thanks to the schematics provided on HackaBrute.

Modifications Include:

  • Filter FM via Triangle and Saw Oscillator Waveforms; Whitenoise Generator.

  • Pitch Modulation via the Filter Envelope and Whitenoise Generator.

  • LFO Rate Modulation via Filter Envelope, Keyboard CV, Mod Wheel CV,  Aftertouch CV, and External CV input.

  • Oscillator Hard Sync Input

  • Switchable Vibrato Rate: Audio, Sub Audio.

  • Buffered outputs for Mod Wheel CV, Aftertouch CV, Filter Envelope, LFO.