BRENSO

Frap Tools 30HP

OSCILLATOR VCO WAVESHAPER WAVEFOLDER LFO

Dual analog complex oscillator. Two triangle-core VCOs with through-zero + exponential FM, Lock/Flip Sync, a four-bus modulation routing, Triangle Shaper, PWM + Pulse Shaper, Wavefolder with Ping, and AM/RM. Green section also runs as sub-audio LFO.

Patch Ideas · 12

★ Complex-OSC lead

Mutual semi-normalled TZFM between yellow and green, shaped through Triangle Shaper into a cranked Wavefolder, tracked by the V/oct sequence.

Walkthrough

Patch Sequencer Pitch CV → BRENSO V/Oct Input.
Set yellow Frequency Scale to audio (green Frequency Scale switch up = audio).
Tune green Coarse Frequency roughly one octave + a fifth above yellow by ear (Phase Relationship LED helps).
Leave Linear TZ FM In unpatched on both oscillators — semi-normal routes each oscillator's sine into the other's TZFM.
Set FM Deviation knob to noon, Linear TZFM Attenuator (yellow) to ~2 o'clock, Exponential FM Attenuator fully CCW.
Set Triangle Shaper knob to noon (triangle), Wavefolder Source to fully CCW (triangle-shaped side), Wavefolder knob to ~3 o'clock.
Set AM/RM knob fully CCW so Final passes dry Timbre.
Patch BRENSO Final Output → VCA Input, Envelope → VCA CV, VCA Out → monitor.

Signal out Final Output — Timbre-processed yellow signal, ±5 V, tracks V/oct.

Listen for A bright, animated lead: pitched notes come through with a complex, evolving harmonic spectrum that shifts as mutual FM and folding interact. Back Linear TZFM Attenuator off toward noon for softer, more singing tones.

▸ Show diagram

Self-pinging kick

Clock triggers Wavefolder Ping with a long decay so the fold envelope itself shapes a percussive body at kick frequency.

Walkthrough

Flip green Frequency Scale switch down to LFO (not strictly needed, but frees green as a modulator).
Set yellow Coarse Frequency to ~50 Hz (lowest range, left-hand graphics).
Set Triangle Shaper knob to noon, Wavefolder Source fully CCW (triangle side).
Set Wavefolder knob fully CCW — Ping will add the folds on each trigger.
Set Wavefolder Ping Decay fully CW for a long fold tail.
Patch Clock/Trigger → BRENSO Wavefolder Ping Input.
Patch BRENSO Final Output → VCA Input, same Clock → Envelope → VCA CV for the amplitude shape.
Patch VCA Out → monitor.

Signal out Final Output — a pinged, decay-shaped kick, ±5 V, pitched by yellow Coarse.

Listen for A punchy analog kick: each trigger blooms the wavefolder open and decays back to a clean fundamental. Shortening Ping Decay tightens the click; raising yellow Coarse moves from sub-kick to tom territory.

▸ Show diagram

Flip-sync noise oscillator

Green Sync set to Flip while noise jitters its exponential FM — yellow's duty cycle flips green's core direction at wildly varying rates.

Walkthrough

Set yellow Coarse Frequency to a mid-range pitch (say 220–440 Hz).
Set green Frequency Scale to audio.
Set green Sync Switch to Flip (up or down per panel — it's the 3-way switch's Flip position).
Patch White/Pink Noise source → BRENSO green Exponential FM Input.
Raise green Exponential FM Attenuator to ~2 o'clock.
Leave FM Deviation knob at noon, Linear TZFM Attenuator fully CCW.
Patch BRENSO green Sine Output → Filter Input → monitor.

Signal out Green Sine Output — pitch-chaotic flipped waveform, ±5 V.

Listen for Harsh, grainy, inharmonic drone with constant articulation changes. Lower the Exponential FM Attenuator toward CCW for calmer sync textures; raise it for full noise-music chaos.

▸ Show diagram

★ TZFM modulator sequencing

Two quantized sequences drive yellow V/oct and a separate VCO feeding yellow's Linear TZ FM — true two-operator FM voices.

Walkthrough

Patch Sequencer 1 Pitch CV → BRENSO Yellow V/Oct Input.
Patch Sequencer 2 Pitch CV → Quantizer Input → external VCO V/Oct.
Patch that external VCO's sine → BRENSO Yellow Linear TZ FM Input (this breaks the semi-normal).
Set FM Deviation knob to noon.
Turn yellow Linear TZFM Attenuator fully CW, yellow Exponential FM Attenuator fully CCW.
Set Triangle Shaper knob to noon, Wavefolder knob to ~10 o'clock (light fold).
Patch BRENSO Final Output → Filter → Output.

Signal out Final Output — two-operator FM voice tracking Sequencer 1, spectrum shaped by Sequencer 2.

Listen for Bell-like, DX-flavoured timbres where carrier pitch follows Seq 1 and sideband structure follows Seq 2. Drop yellow Linear TZFM Attenuator to reduce brightness; raise FM Deviation for metallic clangs.

▸ Show diagram

Snappy exponential FM

Fast envelope into yellow's Exponential FM jack gives a pitched bloom on every gate — classic tonal percussion.

Walkthrough

Set yellow Coarse Frequency to ~40 Hz (lowest range).
Patch Gate source → Envelope Generator trigger.
Patch Envelope Out → BRENSO Yellow Exponential FM Input (breaks the semi-normal).
Raise yellow Exponential FM Attenuator to ~2 o'clock.
Set FM Deviation knob to noon.
Set Triangle Shaper knob to CCW (sine side) for a pure bloom.
Set Wavefolder knob CCW, AM/RM knob CCW.
Patch BRENSO Final Output → VCA Input, Envelope → VCA CV, VCA Out → monitor.

Signal out Final Output — tonal drum with exponential pitch sweep, ±5 V.

Listen for An 808-style tonal percussion with a sharp pitched click. Raise the Exponential FM Attenuator for longer pitch sweeps; shorten the envelope decay for tighter pop.

▸ Show diagram

Self-patched feedback timbre

Final Output back into Mod Bus Input with a slow LFO sweeping the Mod Bus VCA — BRENSO modulates its own Timbre stages.

Walkthrough

Patch BRENSO Final Output → BRENSO Modulation Bus Input (breaks the green-sine semi-normal).
Leave all four Timbre CV jacks unpatched (Triangle Shaper CV, PWM CV, Pulse Shaper CV, Wavefolder Source CV, Wavefolder CV) so they receive the Mod Bus via semi-normal.
Set Modulation Bus Level knob fully CW (VCA wide open).
Patch slow LFO → BRENSO Modulation Bus Level CV Input.
Turn Modulation Bus Level CV Attenuverter CW by ~50%.
Set yellow Coarse Frequency to a sustained audio pitch; set Triangle Shaper noon, Wavefolder knob ~1 o'clock.
Patch BRENSO Final Output → Filter Input → Output.

Signal out Final Output — self-modulating feedback spectrum, ±5 V.

Listen for Chaotic, self-oscillating textures that breathe in and out as the LFO opens the feedback VCA. Lower Modulation Bus Level CV Attenuverter for controlled shimmer; raise it for full dissonant collapse.

▸ Show diagram

Noise-modulated wavefolder

Pink noise into Wavefolder CV adds random micro-folds on top of a clean baseline — analog shimmer.

Walkthrough

Patch Sequencer Pitch CV → BRENSO V/Oct Input.
Set yellow Coarse Frequency to a sustained mid pitch.
Set Triangle Shaper knob to noon, Wavefolder Source to ~noon.
Set Wavefolder knob fully CCW (clean baseline).
Patch Pink Noise source → BRENSO Wavefolder CV Input (breaks Mod Bus semi-normal for this destination).
Set AM/RM knob CCW for dry Timbre.
Patch BRENSO Final Output → Output.

Signal out Final Output — clean tone with stochastic fold grain, ±5 V.

Listen for A sustained tone with an analog-chorus-like shimmer — tiny random fold events sprinkle highs across the spectrum. Swap pink for white noise for brighter grain; add a slow LFO to Wavefolder Symmetry CV for swimming stereo feel.

▸ Show diagram

Complex LFO modulation matrix

Green in LFO mode provides four phase-related modulation outputs plus the Mod Bus — one module, five destinations.

Walkthrough

Flip green Frequency Scale switch down to LFO.
Set green Coarse Frequency to a slow cycle (~1–2 Hz).
Leave Modulation Bus Input unpatched (semi-normal = green sine) and set Modulation Bus Level fully CW.
Patch BRENSO Modulation Bus Output → external Filter Cutoff CV.
Patch BRENSO green Triangle Output → external VCA CV.
Patch BRENSO green Square Output → external Clock Divider Input.
Patch BRENSO green Sawtooth Output → external Reverb Time CV.
Tune yellow as your audio voice and patch Final Output → Filter.

Signal out Four green outputs (sine via Mod Bus, triangle, square, saw) plus green sine itself — all running as slow LFOs, ±5 V.

Listen for A whole patch breathes in sync: filter sweeps on the sine, amplitude pulsates on the triangle, gate-divided rhythm from the square, and reverb-time ripples on the saw. Slow green Coarse further for drone evolution; raise it for motorik pulsing.

▸ Show diagram

★ Classic dual-VCO ring mod

AM/RM switch to 4-quadrant, AM/RM knob full CW — Final carries only the ring-modulated product of yellow's Timbre and green's sine.

Walkthrough

Patch Sequencer Pitch CV → BRENSO V/Oct Input.
Set green Frequency Scale to audio.
Tune green Coarse to a musical interval above yellow (a fifth or a minor third works).
Leave AM/RM Input unpatched — semi-normal pulls in green sine as the modulator.
Set AM/RM Switch down (4-quadrant / Ring).
Set AM/RM knob fully CW (only ring-modulated signal reaches Final).
Set Triangle Shaper noon, Wavefolder CCW, PWM noon.
Patch BRENSO Final Output → VCA Input, Envelope → VCA CV, VCA Out → monitor.

Signal out Final Output — four-quadrant ring-modulated spectrum, ±5 V.

Listen for Classic bell and metallic FM-adjacent tones with strong inharmonic sidebands. Move AM/RM switch up (2-quadrant) for softer AM tremolo instead of ring; change green's interval for completely different harmonic colours.

▸ Show diagram

Lock sync for drift-free stacks

Both oscillators tuned to unison with green Sync → Lock so the digital correction keeps them from drifting apart over time.

Walkthrough

Patch Sequencer Pitch CV → BRENSO V/Oct Input.
Set green Frequency Scale to audio.
Tune yellow Coarse and green Coarse to the same note (Phase Relationship LED slows to a crawl when near unison).
Set green Sync Switch to Lock (up position).
Use green Fine Frequency for micro-detune (not affected by Frequency Lock).
Patch BRENSO yellow Sine Output → Mixer Input 1.
Patch BRENSO green Sine Output → Mixer Input 2.
Patch Mixer Out → Filter → Output.

Signal out Yellow Sine + Green Sine mixed — two locked oscillators in stable unison, each ±5 V.

Listen for A thick, stable unison with controllable beating. Add green Fine detune for chorused width; disable Lock briefly to hear the drift it was hiding.

▸ Show diagram

PWM at audio rate

Green sine, in audio mode, semi-normalled into PWM CV animates yellow's duty cycle at audio rate — screaming FM-PW timbres.

Walkthrough

Set green Frequency Scale to audio, green Coarse to a musical interval against yellow.
Patch Sequencer Pitch CV → BRENSO V/Oct Input.
Leave PWM CV jack unpatched — Mod Bus semi-normal feeds green sine into PWM CV.
Set Modulation Bus Level knob CW (VCA open); leave Modulation Bus Input unpatched.
Set Pulse Width knob near noon.
Set PWM Source Switch up (Triangle Shaper feeds PWM) or down (pure triangle) — try both.
Set Pulse Shaper knob fully CW for bright tone; Square/Shaped Pulse Switch up (shaped) so Final carries the PWM path.
Patch BRENSO Final Output → Filter → Output.

Signal out Final Output — audio-rate PWM'd, Pulse-Shaped yellow signal, ±5 V.

Listen for Screaming, reedy, FM-pulse textures that morph with green's pitch. Drop green to LFO mode for classic slow PWM; back off Modulation Bus Level to tame the harshness.

▸ Show diagram

Integrator glide split

One V/oct feeds yellow directly while an offset CV into the V/Oct Integrator delays green's pitch — built-in glide between the two oscillators.

Walkthrough

Patch Sequencer Pitch CV → BRENSO V/Oct Input (shared with green through the Integrator).
Set green V/oct Integrator Level knob to ~2 o'clock (audible glide).
Patch a CV offset (e.g., sequencer aux out) → BRENSO V/Oct Integrator CV Input to shift green by a variable amount.
Set both Frequency Scale switches to audio; tune green Coarse a fifth above yellow.
Leave Sync Switch off (free).
Set Triangle Shaper noon, Wavefolder ~10 o'clock.
Patch BRENSO yellow Square Output → Voice L, BRENSO green Sawtooth Output → Voice R for a stereo split.

Signal out Yellow Square (crisp pulse) and Green Sawtooth (lagged, glided saw), each ±5 V.

Listen for A stereo dual-VCO patch where the right channel lags into each note with smooth portamento. CCW the Integrator knob to kill the glide; CW it for long slow pitch smears.

▸ Show diagram

Behaviors

Triangle-core through-zero linear FM patch signal into Linear TZ FM In (or leave semi-normalled)

Both oscillators are triangle-core with true through-zero linear FM — modulator crossing zero reverses carrier phase instead of folding. Preserves pitch when modulated by bipolar signals. Default semi-normal uses the opposite oscillator's sine, enabling complex-OSC-style mutual FM without external patching.

Mixed linear + exponential FM raise both LinTZ and Expo attenuators

FM Deviation knob applies the total FM amount; the per-oscillator LinTZ and Expo attenuators choose the blend. Any combination of linear-TZ and exponential FM is available on each carrier simultaneously — not one-or-the-other. Patch separate signals into Lin and Expo inputs to use up to four FM sources per oscillator.

Lock sync (pitch correction) Sync Switch → Lock

Digital correction that uses the primary's square wave to subtly shift the secondary's core thresholds. Fixes tracking drift when secondary is within a semitone of a desired integer ratio. Preserves waveform — unlike classic hard sync it does not create harsh spikes.

Flip sync (reverse sync) Sync Switch → Flip

At each primary duty-cycle edge, the secondary's triangle core reverses direction instead of resetting. Produces complex waveforms with articulation sharper than hard sync but without the full-cycle discontinuity. Not phase-based — no preferred frequency ratio, so primary frequency can sit above or below the secondary.

Coarse Frequency Lock press Coarse Frequency Lock button

Samples the coarse knob position and ignores subsequent movement. Fine knob + CV inputs still work. Prevents accidental pitch bumps during performance. Press again to recall the knob's live value — without this, moving the knob after unlock jumps to its physical position.

V/oct Integrator green Integrator knob off fully CCW

Patches into the green V/oct path behind an integrator. CCW: no lag (normal tracking). CW: increasing glide — green tracks the same V/oct but with asymmetric smoothing. Patch an extra CV into V/Oct Integrator CV input to offset green by a variable amount for automated detuning or octave jumps.

Four-bus modulation routing patch or leave semi-norm on Timbre CV inputs

Modulation Bus (green-sine default source → VCA) feeds all four Timbre CVs (Triangle Shaper, Pulse Shaper, Wavefolder Source, Wavefolder). Patching any Timbre CV jack breaks the normal for that destination only. Enables single-VCA dynamic timbre control with FM-like spectral changes from the level CV.

Wavefolder Ping trigger / gate into Ping input

Rising edge excites the wavefolder through a nonlinear decay envelope. The fold amount swells then decays at the Ping Decay rate. Creates natural-sounding percussive timbres from a steady oscillator — acoustic instruments' decay-spectrum behaviour mimicked without an external envelope.

AM / RM final stage AM/RM switch + modulator at AM/RM In

Two-quadrant (AM): green sine only modulates positive half, giving classic amplitude modulation. Four-quadrant (RM): all four quadrants, ring modulation of the Timbre signal by green sine. AM/RM knob is a crossfader between the Timbre signal and its amplitude-modulated copy — fully CCW passes Timbre dry.

Green as complex LFO Frequency Scale switch (green) → LFO

Green oscillator drops into sub-audio. Its sine/triangle/saw/square remain, and its signal is still available as the default modulator for the Timbre bus and AM/RM — turning BRENSO into a one-module modulation matrix (complex LFO + oscillator) with no external LFO needed.

Self-modulating timbre patch Yellow Final Output into Mod Bus Input

Feeds BRENSO's own final output back into the Mod Bus. The Timbre stages are modulated by the post-processed signal itself. Combined with the Level VCA and envelope, this produces self-oscillating wavefolder textures and chaotic feedback timbres.

Sawtooth only on green inspect outputs

Yellow provides sine, triangle, square/shaped pulse, and Final. Green adds a sawtooth output (sine, triangle, saw, square). Asymmetric output set between oscillators — remember that only green gives saw; yellow's sawtooth-equivalent is the Pulse Shaper output.

Controls

per oscillator (yellow, green)	Coarse Frequency	Primary tuning knob. audio rate: 27.5 Hz – 7040 Hz · LFO mode (green): 0.15 Hz – ~40 Hz
per oscillator	Fine Frequency	Fine offset. Not affected by Frequency Lock. ±1 semitone · always live
per oscillator	Coarse Frequency Lock	Button freezes digital sample of current Coarse voltage; subsequent knob twists are ignored until unlocked. LED shows lock state (green for green VCO, yellow for yellow)
Green oscillator	Frequency Scale (LFO) Switch	Moves green into sub-audio range for complex LFO use. audio: 27.5 Hz – 7040 Hz · LFO: ~0.15 Hz – ~40 Hz · factor ~176×
per oscillator	FM Deviation	Overall FM amount for the per-oscillator bus. sums linear TZFM and exponential FM · range in Hz (not index)
per oscillator	Exponential FM Attenuator	Scales the exponential FM source. fully CCW: no expo FM · audio/CV · default source: other oscillator's sine
per oscillator	Linear TZFM Attenuator	Scales the through-zero linear FM source. fully CCW: no lin-TZ · default source: other oscillator's sine
Green oscillator	V/oct Integrator Level	CCW → +0, CW → slew-lag applied to yellow's V/oct onto green (glide/integrator). time-lag drift · CW: longer integration
Global	Phase Relationship LED	Red LED displays acoustic beats between the two oscillator frequencies. visual tuner / fine-tuning aid
Green oscillator	Sync Switch	Three-way sync selector for green synced to yellow. Lock: digital pitch-error correction · off: free · Flip: inverts waveform direction on primary's duty cycle
Yellow oscillator	Sync Jumper (back)	Selects yellow's sync source (Lock or Flip) when external signal hits yellow Sync In. set at build · Lock (default) or Flip
Yellow oscillator	Square / Shaped Pulse Switch	Selects whether Square out and internal source are the pure square or the Pulse-Shaped square. up: Pulse-Shaped · down: raw square
Timbre (yellow path)	Triangle Shaper	Three-way mix of sine, triangle, and a logarithmic wave. CCW: sine · noon: triangle · CW: log · CV via Triangle Shaper CV · attenuator per CV
Timbre (yellow path)	Pulse Width	Comparator threshold — the PWM amount. center: ~50% symmetry · CW/CCW: asymmetric duty cycle
Timbre (yellow path)	PWM Source Switch	Selects what feeds the PWM comparator: Triangle Shaper output (modulated pulse) or pure yellow triangle (classic PWM). up: Triangle Shaper · down: pure triangle
Timbre (yellow path)	Pulse Shaper	Second waveshaper applied to the PWM output. Emphasises high or low harmonics of the pulse. CCW: bright highs · noon: neutral · CW: low-harmonic emphasis
Timbre (yellow path)	Wavefolder Source	Crossfader between Triangle Shaper and Pulse Shaper signals entering the wavefolder. CCW: triangle-shaped · CW: pulse-shaped · noon: 50/50 · wavefolder improves when fully at one side
Timbre (yellow path)	Wavefolder	Adjusts number of folds. CCW: clean (no folds) · CW: maximum folds · range split into six layout graphics
Timbre (yellow path)	Wavefolder Ping Decay	Exponential decay of the trigger envelope used to excite the wavefolder. CCW: fast decay · CW: slow tail
Timbre (yellow path)	Wavefolder Symmetry	Biases folds toward positive or negative half-cycle (unbalanced folding). noon: symmetric · CW: fold positive more · CCW: fold negative more
Timbre Modulation Bus	Modulation Bus Level	VCA on the modulation source feeding all four Timbre CV inputs. CCW: fully closed (VCA shut) · CW: unity · CV via F.4
Amplitude	AM/RM Switch	Two- or four-quadrant operation of final multiplier. up: 2-quadrant AM · down: 4-quadrant ring mod
Amplitude	AM/RM CV Attenuverter	Scales the AM/RM modulator CV input. bipolar · affects crossfade between Timbre and modulated signal

I/O

IN · 17

V/Oct Input 1 V/oct · >90 kΩ impedance CV

Pitch CV, 1 V/oct tracking over >6 octaves.
V/Oct Integrator CV ±10 V · 7 V knob offset CV

Sums into the green integrator for delayed/glide V/oct lag.
FM Deviation CV ±10 V · 5 V knob offset · attenuverter CV

CV over the total FM deviation amount.
Exponential FM Input audio/CV · >90 kΩ CV

External exponential FM source. Semi-normalled to other oscillator's sine.
NORM → other oscillator's sine
Linear TZ FM Input audio/CV · >30 kΩ CV

External through-zero linear FM source. Semi-normalled to other oscillator's sine.
NORM → other oscillator's sine
Sync Input min 2 Vpp · ±5 V suggested

External signal drives the selected sync behaviour for its oscillator.
Triangle Shaper CV ±10 V · 7 V knob offset · semi-normalled to Mod Bus output CV

Modulates the Triangle Shaper position.
PWM CV ±10 V · 4.5 V knob offset · semi-normalled to Mod Bus output GATE

Modulates the Pulse-Width comparator threshold.
Pulse Shaper CV ±10 V · 9 V knob offset GATE

Modulates the Pulse Shaper.
NORM → Mod Bus output when unpatched
Wavefolder Source CV ±10 V · 7 V knob offset CV

Modulates the source crossfader.
NORM → Mod Bus output when unpatched
Wavefolder CV ±10 V · 10 V knob offset CV

Modulates the fold amount.
NORM → Mod Bus output when unpatched
Wavefolder Symmetry CV ±10 V · >50 kΩ CV

Modulates fold asymmetry.
Wavefolder Ping Input trigger/gate · >90 kΩ GATE

Trigger fires the wavefolder's nonlinear decay envelope, modulating the fold amount.
AM/RM Input ±5 V suggested CV

External modulator for the final amplitude-modulation section.
NORM → green sine when unpatched
AM/RM CV Input ±10 V · 6 V knob offset CV

CV over the AM/RM crossfade.
Modulation Bus Input audio/CV CV

Source feeding the internal VCA and four-destination Timbre bus.
NORM → green sine when unpatched
Modulation Bus Level CV ±10 V · 6 V knob offset · attenuverter CV

CV over the Mod Bus VCA.

OUT · 7

Sine (yellow) / Sine (green) ±5 V · unloaded

Per-oscillator sine output.
Triangle (yellow) / Triangle (green) ±5 V · triangle-core native

Per-oscillator triangle output.
Square (yellow) / Square (green) ±5 V

Per-oscillator square output.
Sawtooth (green) ±5 V · symmetry trimmable

Green-only sawtooth output.
Square / Shaped Pulse (yellow) ±5 V GATE

Switch-selected: raw yellow square, or PWM + Pulse-Shaper result.
Modulation Bus Out ±5 V CV

Post-VCA Mod Bus signal. Fed to the four Timbre CV inputs via semi-normal.
Final Output ±5 V · pre-mixer level GATE

Yellow's processed signal after Triangle Shaper, Pulse Shaper, Source crossfader, Wavefolder, and AM/RM.

Patch Ideas · 12

Behaviors

Controls

I/O

▸ IN · 17

◂ OUT · 7

IN · 17

OUT · 7