OSCar40
Introduction
The OSCar40 is a comprehensive monophonic synthesizer and sequencer that combines the warmth of analogue components with digital stability. DCO-based tuning is quartz crystal derived — no auto-tune required, no drift when things warm up. Voices stay exactly as they were programmed.
Think of the OSCar40 as three instruments in one case: a full-featured monophonic synthesizer, a programmable memory unit storing voices and waveforms, and an independent sequencer with up to 22 sequences running simultaneously.
The Synthesizer
A conventional-layout monophonic synth with performance features built in: semi-tone transposition via keyboard, push-button octave selection, arpeggiator with hold, and duophonic mode letting both oscillators play independently. The waveform building facility — constructing oscillator waveforms harmonic-by-harmonic — is genuinely unusual and powerful.
The Memory Unit
108 pre-programmed voices across 3 ROM banks (36 each), plus 2 RAM banks for user voices. 5 pre-set special waveforms available immediately. Any voice can be modified and stored to a programmable location. Memory is battery-backed and survives power-off.
The Sequencer
Up to 22 independent sequences stored simultaneously. Full edit functions: step up/down, insert, delete, replace. 10 of the 22 can chain the other 12, with optional voice changes embedded — complete musical pieces from modular building blocks. A repeat event command further conserves the 1500-event capacity.
Starting to Play
On power-up the centre OCTAVE lamp lights (8ft register). The last selected voice loads automatically. From factory, VOICE 1 of ROM BANK 1 loads first.
How the Controls Work
The key principle: holding a push-button (VOICE, INTERVAL, SEQ, OSC1, etc.) tells the system to interpret the next key press as a command rather than a note. Keys are numbered −12 to 24 on the top panel. Get used to this scheme early — it's used throughout.
Selecting Voices
Set TRIGGERING to SG or MULT, FUNCTION to NORM. Hold VOICE button, press any key from −12 to 24 (excluding 0 = Panel Voice). Release both. The voice loads immediately.
Loading ROM Banks
Hold TUNE/TRANSPOSE, then press key A (11), B (12), or C (13) to select ROM Bank A, B, or C. Switching banks doesn't change the current voice — you must then select a new voice from the loaded bank.
Transposing Oscillators
Hold INTERVAL, press any key in the TUNE AND TRANSPOSE RANGE (keys −7 to 7) to transpose OSC2 by that many semitones. Press and release INTERVAL without a key to return to 0. The TUNE/TRANSPOSE button does the same for both oscillators together (global pitch shift).
The Edit Find Display
After loading a stored voice, knobs are likely in the wrong physical positions. Hold STORE and turn any knob — the OCTAVE display guides you: LEDs light from the left or right to show which direction to turn. When all LEDs go out together, the knob has reached the stored value and you have manual control. Release STORE and edit freely.
Arpeggiator Quick Start
Set FUNCTION to ARP. Hold keys down — they arpeggiate while held. Set FUNCTION to HOLD A for indefinite hold. Press INSERT to enter MEMORY mode (notes persist after release); press DELETE to return to HANDS-ON mode. Direction: press ▼STEP for DOWN only; press STEP▲ (with a key held) for UP only; press both STEP buttons together to return to UP/DOWN.
Duophonic Mode
Set FUNCTION to DUO. Play two keys — each oscillator takes one note. One key still plays both oscillators unison. Store a voice with DUO active to recall it instantly.
Simple Sequences
Hold SEQ + STORE, press key 1 to enter edit mode for Sequence 1. OCTAVE display reverses to confirm edit mode. Press INSERT + DELETE to clear the sequence. Play notes (SPACE button = rest). Press both STEP buttons together to exit edit mode. Press STEP▲ to start playback. Press STEP▲ again while playing for endless loop. Press ▼STEP to stop.
Oscillators
Both DCOs track together via keyboard and sequencer. In DUO or sequence accompaniment mode, OSC2 operates independently from OSC1.
| Control | Function |
|---|---|
| FINE TUNE | Raises or lowers both oscillators up to ±1 semitone. Not stored in voice memory. |
| OCTAVE SHIFT | OSC2 only. Sets octave offset from −2 to +3 relative to OSC1. Maintained when OCTAVE buttons are used. |
| DETUNE | OSC2 only. Fine pitch difference up to ±1 semitone. Small centre dead band for easy zero-finding. |
| TUNE/TRANSPOSE | Both oscillators, ±7 semitones via keyboard. Press and release without key = return to 0. |
| INTERVAL | OSC2 only transpose, ±7 semitones. Press and release without key = return to 0. Voice 20 ships with +5 semitones. |
| OCTAVE buttons | 5 positions: 32ft / 16ft / 8ft / 4ft / 2ft. Stored in voice. |
Waveforms
| Position | Waveform |
|---|---|
| 1 | Triangle |
| 2 | Sawtooth (ramp) |
| 3 | Square |
| 4 | Variable pulse width (static — set by PW knob) |
| 5 | PWM — pulse width modulated by independent internal LFO |
| 6 (OSC1) | OFF — OSC1 silent |
| 6 (OSC2) | OSC2 copies OSC1 waveform |
Pulse Width
Active only when waveform is set to position 4 or 5.
Position 4 (variable): PW knob sets static pulse width from 50% (square) fully anticlockwise to very narrow fully clockwise.
Position 5 (PWM): PW sets the depth of modulation above and below 50%. The modulating signal is a triangular wave from an independent internal LFO (one per oscillator) whose rate is tied to the note pitch — not the main TEMPO or LFO. The two oscillators run at slightly different rates for richness.
Additional PWM Rates
| Key Combo | Result |
|---|---|
| TUNE/TRANSPOSE + key 19 (R1) | PWM slowest rate |
| TUNE/TRANSPOSE + key 20 (R2) | PWM slower rate |
| TUNE/TRANSPOSE + key 19 again | PWM normal rate |
| TUNE/TRANSPOSE + key 19 again | PWM faster rate |
Special Waveforms
Hold OSC1 or OSC2 button and press keys −3 to −7 for pre-set special waveforms. Keys −8 to −12 access programmable waveforms built via harmonic addition. Key 0 enters waveform edit mode. Both OSC buttons can be held simultaneously to assign the same special waveform to both oscillators at once. See Section 8 for full waveform building reference.
Filter
The OSCar40 filter is actually two 12 dB/octave filters whose cutoff frequencies track together but can be separated. This gives access to both the punch of a 24 dB/oct filter (zero separation) and the rounder character of 12 dB/oct, with bandpass and resonance adding a further dimension.
| Control | Function |
|---|---|
| TYPE | LP (24dB low pass), HP (24dB high pass), BP (12dB bandpass), and NO TRACK versions of each (positions 4–6). NO TRACK = filter does not follow keyboard pitch. |
| SEPARATION | Spreads the two filter cutoffs apart — 0 to ~4 octaves. Zero = both filters act as one 24dB filter. In LP/HP increasing separation softens the slope to 12dB. In BP it widens the bandpass. High Q + separation creates two distinct resonant peaks. |
| FREQUENCY | Manual cutoff: full audio range 16Hz – 16kHz. Both filters move together maintaining any separation set. |
| Q | Resonance of both filters. At maximum, filters self-oscillate — producing a note with oscillators fully off. High Q + modulation gives strong wah-wah or vowel effects. |
| AMOUNT | Filter envelope (Env 2) modulation amount. Centre = zero. Clockwise = envelope sweeps upward; anticlockwise = downward. |
Envelopes & Triggering
Two ADSR envelope generators. Env 1 (upper) controls VCA (volume). Env 2 (lower) controls filter cutoff frequency and, via the LFO waveform ENV routing, oscillator pitch.
Envelope 1 — Volume
| Control | Range | Notes |
|---|---|---|
| ATTACK | <1ms – 15s | Linear rise. Triggered on key press (or clock/external). |
| DECAY | <1ms – 60s | Exponential fall to sustain level. Stops at sustain if set above zero. |
| SUSTAIN | 0 – max | Level held while gate is on (key held down or auto gate time active). |
| RELEASE | <1ms – 60s | Exponential fall to zero after gate off. If release starts below max, time is proportionally shorter. |
Envelope 2 — Filter (+ Pitch)
Same ADSR controls affecting filter frequency sweep. Two differences from Env 1:
Attack: Exponential (not linear), range up to 60 seconds.
Delay mode: When SUSTAIN is set to zero, RELEASE control becomes a pre-attack DELAY (0–1 second). The attack won't start if the gate goes off before the delay completes. Useful for delayed filter sweeps and echo-type effects.
Triggering Modes
| Switch Position | Behaviour |
|---|---|
| SG (Single) | Both envelopes triggered by keyboard only if NO other key is down. Programmable in voice. |
| MULT (Multiple) | Both envelopes triggered every time any key takes effect. Most useful general setting. Programmable in voice. |
| RPT1 | Env 1 (volume) triggered by TEMPO clock while a key is held. Env 2 from keyboard. |
| RPT2 | Env 2 (filter) triggered by TEMPO clock unconditionally. Env 1 from keyboard. |
| RPT1&2 | Both envelopes triggered by TEMPO clock. Simulates repeated key presses rhythmically. |
| EXT | Both envelopes triggered by external trigger pulses. TEMPO knob becomes EXTERNAL TRIGGER DIVIDE (1, 2, 3, 4, 6, 8, 12, or 16). |
Tempo and Gate Time
TEMPO controls envelope repeat rate, arpeggiator speed, and sequence playback speed — range 6 to 1800 BPM. Fully anticlockwise disables the internal clock and activates the EXTERNAL TRIGGER IN jack.
GATE TIME simulates key-hold duration during sequence playback and envelope repeats. Range: 30ms to 8 seconds. BEAT LED illuminates during each tempo pulse and stays lit during auto gate time.
LFO & Modulation
The LFO routes to oscillator pitch and filter frequency independently. Two paths into each destination: automatic (INTRO delayed) and joystick-controlled. They can work together, adding or cancelling.
LFO Waveforms
| Position | Waveform / Source |
|---|---|
| 1 | Triangle — smooth bidirectional sweep |
| 2 | Sawtooth — rising then instant drop |
| 3 | Square — modulates in one direction only (useful for trills without pitch drift) |
| 4 (ENV) | Uses Filter Envelope (Env 2) output as modulation source |
| 5 (KBD) | Keyboard pitch CV — allows adjustment of keyboard tracking or filter tracking |
| 6 (R) | Random (sample-and-hold) — new random level on each LFO cycle. RATE controls how often it changes. |
| Control | Function |
|---|---|
| RATE | LFO frequency: 1 cycle/30 seconds to 30 Hz |
| INTRO | Delay before auto modulation starts after a new key press. 0 to ~8 seconds. Affected by single vs. multiple triggering setting. |
| PITCH MOD | Depth of LFO → pitch (auto/INTRO path). Centre = 0. CW = positive, CCW = negative. Max: ±7 semitones. |
| AMOUNT (Filter) | Depth of LFO → filter frequency (auto/INTRO path). Max: ±full filter range. Affected by INTRO delay. |
OSC1 LFO Modulation Enable
By default both oscillators receive LFO pitch modulation. OSC1 can be disabled/enabled separately:
TUNE/TRANSPOSE + key 23 Enable LFO modulation of OSC1
TUNE/TRANSPOSE + key 24 Disable LFO modulation of OSC1
LFO Sync Reset
LFO can reset on each arpeggiator or sequencer step clock. Saved in patch. Default: OFF.
TUNE/TRANSPOSE + key 21 Disable LFO sync
TUNE/TRANSPOSE + key 22 Enable LFO sync
Glide
| Type Position | Name | Behaviour |
|---|---|---|
| 1 | N (Normal) | Standard portamento — smooth glide. Time = per octave. |
| 2 | AUTO | Glide only when last key is still held (legato glide). |
| 3 | GLISS | Glissando — steps through semitones rather than smooth sweep. |
| 4 | FIX N | Normal portamento with fixed total time regardless of interval. |
| 5 | FIX A | Auto portamento with fixed time. |
| 6 | FIX G | Glissando with fixed time. |
TIME: Positions 1–3: 0 to 6 seconds per octave. Positions 4–6: 0 to 1 second over any note span.
Joystick
Self-centring joystick with two axes, each with programmable depth.
| Axis | Control | Range |
|---|---|---|
| BEND (left/right) | BEND AMOUNT | 0 to ±14 semitones (1+ octave in each direction) |
| MOD (up/down) | MOD / PITCH AMOUNT | 0 to ±7 semitone pitch swing |
| MOD (up/down) | MOD / FILTER AMOUNT | 0 to ±full filter range |
Joystick modulation operates independently of INTRO delay and auto modulation. Both paths can be mixed together on pitch and filter — additive or cancelling depending on sign.
Voices & Memory
Memory Structure
| Bank | Type | Voices |
|---|---|---|
| ROM Bank A (key 11) | Read-only pre-sets | 36 |
| ROM Bank B (key 12) | Read-only pre-sets | 36 |
| ROM Bank C (key 13) | Read-only pre-sets | 36 |
| RAM Bank 1 | User programmable | 36 |
| RAM Bank 2 | User programmable | 36 |
Selecting and Storing Voices
Select: Hold VOICE, press key −12 to 24 (excluding 0).
Store: Set up the sound, then hold STORE + VOICE simultaneously, press the target key. That exact sound — every control position — is written to that slot.
The Panel Voice (Voice 0)
Selecting key 0 gives control to the physical panel state. Best used for building voices from scratch. Remember to set TRIGGER to SG or MULT and turn up the VOLUME knob, otherwise you may get no sound.
Moving Voices Between Banks
Select the source voice, then store it to the desired destination voice location in the target bank. Load the new bank first (TUNE/TRANSPOSE + A/B/C), then store.
Editing Voices
After selecting a stored voice, use the EDIT FIND display (hold STORE, turn any knob) to locate where each parameter is set before adjusting. Once you find the value (all LEDs go out), release STORE — you now have direct control of that parameter. Modify freely, then re-store.
Arpeggiator, Duo & Hold
Function Switch Positions
| Position | Mode |
|---|---|
| 1 — NORM | Normal monophonic playing. Programmable in voice. |
| 2 — ARP | Arpeggiator active. Sequences held keys at TEMPO rate. |
| 3 — DUO | Duophonic: each oscillator plays a separate key. |
| 4 — HOLD N | NORM + indefinite hold (gate stays open). |
| 5 — HOLD A | ARP + indefinite hold. Notes arpeggiate indefinitely after release. |
| 6 — HOLD D | DUO + indefinite hold. |
Arpeggiator Modes
HANDS-ON mode: Default. Only held keys arpeggiate. Press DELETE to return to this mode.
MEMORY mode: Press INSERT to activate. Notes added while any key held persist in memory after all keys released. Press new keys to clear and start fresh.
Arpeggiator Direction
▼STEP DOWN only
STEP▲ (with key held) UP only
Both STEP buttons (with key held) UP/DOWN
TUNE/TRANSPOSE + key 8 RANDOM
Duophonic Playing
In DUO mode, one key = both oscillators on same pitch. Two keys = one oscillator per key. Oscillator 2 can be set to a different octave or waveform first for interesting two-voice textures.
Sequence Accompaniment
Start a sequence in loop playback, then switch FUNCTION to DUO. Oscillator 2 plays the sequence; Oscillator 1 is free for keyboard playing. See Section 7.
Sequencer
22 independent sequences. Sequences 1–12 are basic (notes + spaces + repeats). Sequences 13–22 can chain any of sequences 1–12 and embed voice changes — building full pieces from phrase building blocks.
Creating a Sequence
- Hold SEQ + STORE, press key (1–22) to select sequence and enter edit mode. OCTAVE display reverses.
- Press INSERT + DELETE together to clear the sequence.
- Ensure FUNCTION is in NORM.
- Play notes. SPACE button = rest (heard as noise in edit mode).
- Legato playing (overlapping key presses) is recorded and played back identically.
- Press both STEP buttons together to exit edit mode.
Sequence Editing
| Button | Edit Mode Function |
|---|---|
| STEP▲ | Step forward through events |
| ▼STEP | Step backward through events |
| INSERT | Add event at current position |
| DELETE | Delete event at current position |
| INSERT + DELETE | Clear entire sequence |
| REPEAT EVENT + key | Add a repeat (up to 24×) — uses only 1 event space |
| REPEAT EVENT alone | Jump to end of sequence |
Playback
| Action | Command |
|---|---|
| Select sequence for playback | Hold SEQ, press key (without STORE) |
| Start (single play) | Press STEP▲ |
| Set to loop repeat | Press STEP▲ again while playing |
| Stop loop (end of current pass) | Press ▼STEP once |
| Stop immediately | Press ▼STEP twice |
| Change voice during playback | Normal VOICE selection — only works for Sequences 1–12 |
Special Waveforms
Pre-set Special Waveforms
Hold OSC1 or OSC2 button, press keys −3 to −7 to select from 5 pre-set special waveforms. Both buttons simultaneously assigns the same waveform to both oscillators.
Programmable Waveforms
Keys −8 to −12 access 5 programmable waveform slots, built using harmonic addition.
Building a Waveform
- Hold OSC1 (or OSC2), press key 0 to enter waveform edit mode.
- Press CLEAR EDIT (INSERT + DELETE with OSC button held) to start with an empty waveform.
- Hold the OSC button and press HARMONICS keys to insert harmonics (fundamental = key 1, 2nd harmonic = key 2, etc.).
- Each inserted harmonic adds to the waveform; each press of the same key removes it.
- To store: hold STORE + OSC button, press target key (−8 to −12).
Trigger, Gate & External Sync
The TRIGGER is an instantaneous event starting the envelope attack and setting the new pitch. The GATE determines whether envelopes stay open. When triggered from keyboard, gate = open while any key is held. When triggered from clock or external, gate duration = GATE TIME setting.
External Trigger
Set TRIGGERING to EXT, or set TEMPO fully anticlockwise. Connect a trigger source to the EXTERNAL TRIGGER IN jack.
| Signal | Specification |
|---|---|
| Trigger In | Accepts standard gate/trigger pulses. Divide options: 1, 2, 3, 4, 6, 8, 12, or 16 (set via TEMPO knob in EXT trigger mode) |
| Trigger Out | Outputs trigger with optional clock divide — sync other instruments |
External trigger divide (TEMPO knob in EXT mode) lets you use a faster master clock and sub-divide it for the OSCar40 — useful for syncing to drum machines running at multiple of the desired tempo.
MIDI Functions
Standard MIDI In / Out / Thru. All MIDI options are selected via key combinations. Settings are stored per voice.
MIDI Option Summary
| # | Option | Description |
|---|---|---|
| 1 | Performance Joystick | Transmit/receive joystick data (pitch bend, modulation) via MIDI |
| 2 | Program Change | Send/receive MIDI program change messages when voices are selected |
| 3 | Key On/Off | Transmit/receive note data. Can be disabled for clock-only sync setups. |
| 4 | Sequencer & Arpeggiator | Sync sequencer/arp to incoming MIDI clock, or transmit clock |
| 5 | Omni Mode | Respond to all MIDI channels (Omni On) or single channel only |
| 6 | Timing Clock | Send/receive MIDI timing clock messages |
| 7 | Pull-off Note | When a key is released and another is held, retriggering behaviour |
| 8 | MIDI Channel | Assign transmit and receive MIDI channel |
SYSEX Data Transfer
All voices, waveforms, and sequences can be saved and loaded via MIDI SYSEX. To initiate a SYSEX dump: press INSERT to select the data type, then press SPACE to start transmission. Use this for regular backups — the battery keeps data during power-off, but SYSEX gives unlimited external storage.
All Notes Off
The OSCar40 responds to the MIDI All Notes Off message, immediately silencing any stuck or held notes.
MIDI CC Dump
The current voice can be output as a stream of MIDI CC messages representing all parameter values. Useful for capturing the state of a patch for DAW automation or documentation.
MIDI CC Message List
The OSCar40 supports MIDI Control Change for full DAW automation. All CCs correspond to front-panel parameters and are saved in voice memory when a CC dump is performed.
| CC# | Parameter |
|---|---|
| CC 1 | Modulation (joystick MOD axis) |
| CC 5 | Glide Time |
| CC 7 | Volume |
| CC 65 | Glide On/Off |
| CC 70 | Filter Separation |
| CC 71 | Filter Q (Resonance) |
| CC 72 | VCA Release |
| CC 73 | VCA Attack |
| CC 74 | Filter Frequency (Cutoff) |
| CC 75 | VCA Decay |
| CC 76 | LFO Rate |
| CC 77 | LFO Pitch Mod depth |
| CC 78 | LFO Filter Mod depth |
| CC 79 | LFO Intro Delay |
| CC 80 | Filter Envelope Amount |
| CC 81 | Filter Attack |
| CC 82 | Filter Decay |
| CC 83 | Filter Sustain Level |
| CC 84 | Filter Release |
| CC 85 | VCA Sustain Level |
| CC 86 | OSC Balance |
| CC 87 | Noise Balance |
| CC 88 | OSC2 Detune |
| CC 89 | Pulse Width |
| CC 90 | Bend Amount |
| CC 102 | Joystick Pitch Mod Amount |
| CC 103 | Joystick Filter Mod Amount |
Maintenance
Battery Replacement
The memory backup battery is a CR2032 or BR2032 coin cell located on the rear of the MIDI board. It should last several years. Signs of failure: voices, sequences, or waveforms not retained after power-off.
iZotope RX Note (Studio Reference)
If capturing the OSCar40 via the E4XT Ultra sampling path (Apollo 8 Outputs 3&4 → E4XT balanced inputs), any tape-sourced samples can later be processed in iZotope RX for noise reduction and restoration.