References 3 – Eurorack Modules


Since my work will be implemented in a eurorack system I attempted to find references of existing modules that would do a similar thing. As expected I found no modules where Music-Information-Retrieval is implemented. But there are Modules with which like Pichfollowers, envelope-followers, combinations of those two and separate building blocks.

Doepfer a-196 PLL:

The A-196 PLL is a Phase-locked-loop (PLL) module. PLL-circuits are commonly used in pitch-tracker devices. It is a comparative circuit that compares two oscillating signals in their relative Phase. The A-196 is more of a weird oscillator than a Modulation source but it has 3 different parts one of which is a PLL circuit.

Env Followers:

Doepfer A-134-4C, Gap Synthesizer – Envelope Follower, Buchla – 230e Triple Envelope Tracker

These are quite ‚simple‘ envelope followers which take the amplitude of a signal over time and translate it into an envelope. Every module is its own interpretation of controllable parameters like threshold, attack, release or internal triggers (Buchla). As you might recognize the 230e is not a eurorack format, but as there are not many examples I included a Buchla module.

XAOC Devices – Sevastopol 2:

Also an envelope follower but with a twist. It has more functions one of which is an envelope follower but also a comparator module between two signals.

Analogue Systems RS-35N:

Here the envelope follower is combined with a pitch tracker and a trigger which are the basic values to play a synthesizer voice be it percussive or tonal. It also is equipped with its own set of adjustable parameters to control the inputs and outputs of the signal.

Expert Sleepers Disting mk4:

The Disting Mark 4 is a Digital signal processor which provides many algorithms for modular synthesis. One of those algorithms is a pitch and envelope tracker.

Erica Synths Black Input:

Is not an existing module. it is a concept in unclear development stage. The functions it may provide are the following:

  • 1. Balanced inputs withXLR, 6.3mm TRS and 3.5mm TRS
  • 2. Input preamp with adjustable gain and level indicator
  • 3. Envelope follower with adjustable threshold and rate
  • 4. Gate and Trigger outputs
  • 5. Accurate, low latency monophonic pitch tracker
  • 6. Continuous and quantized (by semitones) CV outputs
  • 7. Three pitch tracker models


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