AT101V

Get the highlights.

A filter that sings. The IR3109 four-pole low-pass, with a resonance that self-oscillates in tune.

A sequencer you can see. 100 steps with accent, slide, tie and probability, plus random, mutate and .mid export.

Every slider, every switch. Bender, portamento, transpose and the modulation push, as on the 1982 panel.

What the SH‑101 never had. Polyphony, host sync, chorus, delay, reverb and MIDI learn on every control.

Three classic colours. Grey, blue or red, rendered from measurements of the original.

The film.

AT101V rendered in 3D, in three shots. The sound is the engine playing Acid Line, a sequence preset.

One oscillator, one filter, no shortcuts.

On paper the SH‑101 is simple: a CEM3340 oscillator, a sub-oscillator made of two flip-flops and Roland's IR3109 four-pole filter. Its sound is in the details, and AT101V models them from the service notes and published circuit analysis.

Every value below was measured on the engine and compared with the original documentation.

Filter: IR3109 four-pole low-pass, 24 dB per octave, solved without a one-sample delay in the feedback loop
Resonance: diode-limited feedback that thins the bass like the original and self-oscillates as a sine tracking 1 V per octave
Oscillator: rising saw and pulse from one core; pulse width by hand, by the LFO or by the envelope, down to silence
Sub-oscillator: one or two octaves down, or the 25 % pulse, phase-locked to the oscillator like the flip-flops
Envelope: RC curves; the attack overshoots and stops at the peak. Attack 1.5 ms to 4 s, decay and release up to 10 s
Keyboard logic: last-note or low-note priority set by the trigger switch, Auto portamento only when legato
Oversampling: the whole voice at 2x, 4x or 8x

1+ sub

oscillator, as on the original

100

sequencer steps with accent and slide

8

voices when you want more than one

43

presets, from acid lines to ambient

Hear it.

Every clip is the engine on its own, playing a factory preset from a MIDI file written for it. Nothing added afterwards, only the level matched across clips. Download the MIDI and play it through the preset yourself.

Acid Line
The step sequencer, transposed from the keys every two bars.

0:21 MIDI
101 Bass
A house bass line with octave jumps.

0:16 MIDI
Classic Lead
A legato melody: Auto portamento slides, the mod wheel adds vibrato.

0:12 MIDI
Arp Up
Four chords through the arpeggiator, clocked by the modulator.

0:09 MIDI
Soft Pad
Six voices, PWM and chorus: the SH‑101 as a pad.

0:17 MIDI
Whistle
No oscillator at all: the filter self-oscillates and follows the keys.

0:14 MIDI

Every slider, every switch.

The front panel works the way it did in 1982. The modulator is also the clock of the arpeggiator and the sequencer, the bender pushes forward for vibrato and growl, HOLD sustains, and KEY TRANSPOSE shifts everything, a running sequence included.

A sequencer you can see.

The original records up to 100 steps from the keyboard without showing them. AT101V keeps that workflow and adds a step editor on its own page.

Note grid. Click to place a note, drag to paint, click again for a rest. Up to 100 steps on four pages.
Accent and slide. Accents open the filter and push the amplifier; slides glide into the next note without retriggering.
Probability. Each step can play 25, 50, 75 or 100 % of the time, so a pattern keeps moving.
Tools. Length, rotate, transpose by semitones or octaves, a random bass line generator and a mutate button.
Export. Save the pattern as a .mid file and drop it into your DAW.
Keys transpose. While a sequence runs, any key transposes it.

AT101V Sequencer page with a 16-step acid pattern — The Sequencer page playing Acid Line: accents in orange, slides in green, the red LED marks the current step.

What the SH‑101 never had.

A Settings page, drawn like the panel, adds what a modern studio asks for.

Polyphony and unison. Mono like the original, or up to 8 voices, with up to 4-voice unison, detune and stereo spread.
Host sync. The arpeggiator and the sequencer follow your DAW, with swing and gate length. Or keep the modulator as the clock.
Expression. Velocity to filter and amplifier, accent amount, slide time and arpeggios over up to four octaves.
Effects. Drive into the filter, a BBD-style chorus, a tempo-synced delay and a plate reverb.
MIDI. MIDI learn on every control, mod wheel as the bender push, sustain pedal as HOLD and MIDI out of every note the synth plays.
Presets. Save your own patches, sequence and settings included, or roll a random patch.

AT101V Settings page with faders and LED selectors — The Settings page: voices, expression, clock, character, chorus, delay, reverb and system.

Basses, leads and sequences that play themselves.

8

Bass

Round 101 basses, rubbery ones and driven ones.

7

Lead

Solo voices with portamento, PWM and the singing resonance.

10

Sequences

Acid, electro, Berlin school and probability patterns. They play on their own.

4

Arpeggios

Hold a chord. Latch it with HOLD and transpose it from the keys.

6

Ambient

Slow drones, wind and generative bells with delay and reverb.

8

Poly and FX

Polyphonic brass and keys, sample and hold, zaps and lasers.

Pick a colour.

Grey

Tech specs.

Sound engine

CEM3340-style saw and pulse with PWM, sub-oscillator (−1, −2 oct, 25 % pulse), noise
IR3109 four-pole low-pass with diode-limited resonance
RC envelope, modulator as clock, arpeggiator and 100-step sequencer
2x, 4x or 8x oversampling

Extensions

Visual step editor: accent, slide, tie, probability, random, mutate, .mid export
Up to 8 voices, up to 4-voice unison
Host sync with swing and gate length
Velocity, drive, chorus, delay, reverb
MIDI learn and MIDI out
Grey, blue and red bodies

Formats

VST3, Audio Unit (macOS) and standalone app

Minimum

macOS Mac with Apple silicon (M1 or later), or Intel Core i5 quad-core from 2017 or later, with macOS 11 Big Sur or later.
Windows PC with Intel Core i5-6500 (6th generation, 2015) or AMD Ryzen 5 1600, or better, with Windows 10 or 11, 64-bit.
4 GB of RAM, a 1280 × 800 screen and a 64-bit host for VST3 or Audio Unit, or the standalone app.
Disk space: 63 MB on macOS (all formats), 21 MB on Windows.

Measured CPU load

Setting	Apple M4	AMD Ryzen 9 5900XT
Mono patch, 4x	1.0 %	1.8 %
6-voice pad, 4x	7.8 %	14.5 %
6-voice pad, 8x	14.5 %	27.6 %

Percentage of one CPU core at 48 kHz, sound engine only. With the editor open, the interface adds about 5 % on the M4. Hosts run each instrument on one core, so single-core speed is what counts.

Download AT101V 1.0.1.

Free, no account, no activation, no telemetry.

macOS

macOS 11 or later. Apple silicon and Intel in one universal binary. VST3, Audio Unit and standalone app. 42 MB.

Download for macOS

How to install

Unzip the file.
Copy AT101V.vst3 to ~/Library/Audio/Plug-Ins/VST3.
Copy AT101V.component to ~/Library/Audio/Plug-Ins/Components.
Rescan plugins in your DAW. In Ableton Live: Settings, Plug-Ins, Rescan.

Windows

Windows 10 or 11, 64-bit. VST3 and standalone app. 14 MB.

Download for Windows