VOLT Instruments AG
/lab

A1 — A12

Issue No. 41

Bauschänzlistr. 4

8001 Zürich

VOLT

A catalogue of modular synthesisers, hand-wound transformers, and incidental electronic apparatus. Built one at a time, in Zürich, since nineteen sixty-eight.↓ Catalogue follows

8400 Hz
Cutoff

Module M-21 · live response · low-pass mode

⸺ Module M-21

Triple
State-Variable
Filter.

A two-pole filter, three outputs taken simultaneously. The voltage-controlled resonance is self-oscillating past unity. The circuit is the one Hans Wäcker drew for us in 1974 and we have not had reason to change it.

Width12 HP
Depth32 mm
Power+12V · 60 mA / −12V · 50 mA
OutputsLP · BP · HP, 10 Vpp
ResonanceSelf-osc above 0.86
Slew rate200 V/μs
Frequency range8 Hz – 22 kHz

CHF540.—

In stock · 14

Catalogue. 10 modules.

№ModuleSubHPPrice · CHFStatus
M-21Triple State Variable FilterLow-pass · band-pass · high-pass12540.—● In stock
M-08Dual Sine OscillatorThrough-zero FM14480.—● In stock
M-31Step Sequencer16 steps · two channels20620.—○ Back order
M-04Voltage QuantiserTwelve scales, transposable8320.—● In stock
M-27Spring Reverb, Long TankAccutronics 8FB3A1A14560.—● In stock
M-15Slew Limiter, LogarithmicTwo channels · linked6260.—○ Back order
M-19Mixer, Six ChannelStereo bus, transformer out14460.—● In stock
M-33Wavefolder, DiscreteBC547 cell, no IC8340.—● In stock
M-02Power Supply, Linear±12V, 1A, toroidal—380.—● In stock
M-25Tape Echo, Single HeadDiscontinued after run of 8416—✕ Discontinued

From the workshop —

We build one panel at a time, on the same milling machine we bought from the Sulzer foundry in 1972. If you place an order this week, we will start it on Monday morning, the 26th of May. You will be the second job of the week.

— Hans-Peter Wäcker, master · 24. V. 2026