# Pittsburgh Modular — "Generator" - [Manual PDF](../../manuals/Generator - Pittsburgh Modular Synthesizers.pdf) --- [Manual PDF / Source](https://pittsburghmodular.com/generator) # Pittsburgh Modular Generator — creative patch ideas and combo recommendations The **Pittsburgh Modular Generator** is a compact **dual analog oscillator / FM source / modulation hub** built for unstable, aggressive, and highly animated sounds rather than precise melodic tracking. From the manual: - **2 triangle-core oscillators** - **Internal FM path:** Generator 1’s **Index Out** internally FM’s Generator 2 - **External FM routing:** one external modulation path can be directed to either osc 1 or osc 2 - **Shared shape control:** morphs the two oscillators in opposite directions - Gen 1: square → triangle - Gen 2: triangle → square - **Index section:** a VCA on Generator 1’s output, with CV, whose output both: - appears at **OUT** - acts as the **internal FM source** for Generator 2 - Not 1V/oct, not temp compensated: best approached as a **chaotic voice, percussion engine, drone core, modulation source, and texture oscillator** In practice, Generator excels when treated as: 1. a **cross-influenced dual osc voice** 2. an **FM/noise/percussion source** 3. a **compound modulation module** 4. a **feedback instrument** --- ## What is special about this module musically A few things matter a lot: ### 1. The Index VCA is the heart of the module Generator 1 passes through a VCA-like stage controlled by the **Index knob** and **Index CV**, and that post-VCA signal is used to FM Generator 2 internally. This means: - envelopes into **Index CV** create **dynamic FM bursts** - slow CV into **Index CV** creates **breathing timbre shifts** - audio-rate CV into **Index CV** creates unstable amplitude/FM interactions This is why the module is so strong for: - metallic percussion - tearing basses - unstable drones - game-console-ish zips and sputters ### 2. The shape knob is a macro timbre control One knob simultaneously pushes the two oscillators in **opposite waveform directions**. So with one movement you’re changing: - harmonic content of the modulator - harmonic content of the carrier - FM response character That makes it especially good with: - CV-addressed modulation - manual performance gestures - stepped random - joystick control ### 3. It loves being patched “wrong” Because it isn’t trying to be a precision VCO, it rewards: - self-patching - extreme CV - feedback loops - offset/attenuation tricks - clocking at subaudio or audio edge zones --- # Best module pairings ## 1. Envelope generators / function generators **Highly recommended types:** - Make Noise Maths - Befaco Rampage - Intellijel Quadrax - ALM Pip Slope - Frap Tools Falistri ### Why The Generator’s **Index CV** input is begging for envelopes. This is one of the fastest ways to animate internal FM. ### Results - percussive FM plucks - toms, metallic hits, lasers - dynamic drones with shifting overtones - pseudo-acoustic transient behavior ### Tip Use: - a **snappy envelope** to Index CV - a **slower envelope** to the external FM attenuverter path - then send the external FM to whichever oscillator is not already doing the most interesting thing This gives layered movement: one contour for internal FM intensity, another for pitch/timbre bend. --- ## 2. VCAs and modulation utilities **Recommended types:** - Happy Nerding 3xVCA - Intellijel Quad VCA - Veils - Mutable Instruments Blinds / Joranalogue Select 2 / bipolar VCAs - attenuverters, offsets, mixers ### Why Generator becomes much more powerful when CV is carefully scaled. It can get wild very fast, so utilities turn “chaos” into “playable chaos.” ### Best uses - tame the output before filters/waveshapers - scale random voltages going to Shape or Index CV - create **voltage-controlled external FM depth** - mix Generator outputs with other oscillators before ring mod or filtering ### Especially useful A **bipolar VCA / attenuverter** before the **External Input** lets you automate the amount and polarity of FM going into Gen 1 or Gen 2. --- ## 3. Random / chaos / sample & hold modules **Recommended types:** - Make Noise Wogglebug - Mutable Marbles - SSF Ultra-Random Analog - Joranalogue Orbit 3 - Doepfer A-118 + S&H - noise + slew combos ### Why Generator responds beautifully to irregular but bounded control voltages. ### Great patch targets - **Shape** - **Index CV** - **External FM input attenuverter** via manual or VC processing - oscillator EXP inputs for unstable pitch fields ### Results - clattering, insect-like percussion - animated drones - semi-repeating machine chatter - “broken console” melodies and digital-sounding analog artifacts ### Trick Use **stepped random** to one oscillator’s EXP input and **slewed random** to Index CV. That gives: - stepped pitch regions - continuously changing FM intensity Very effective for evolving electroacoustic textures. --- ## 4. Filters, especially aggressive or character filters **Recommended types:** - MS-20 style filters - Steiner-Parker filters - multimode state-variable filters - low-pass gates - resonant band-pass filters Specific examples: - Bastl Ikarie - Xaoc Belgrad - Doepfer A-124 Wasp - Intellijel Polaris - Make Noise QPAS - LPGs like Optomix, LxD ### Why Generator can make very dense spectra. A good filter turns the chaos into a playable voice. ### Best filter strategies - **Band-pass** for metallic percussion - **Low-pass gate** for woody, struck sounds - **High resonance low-pass** for mutant bass - **Stereo dual peak filter** for drones and moving textures ### Patch idea Take: - **2** (Generator 2 output) into a resonant filter - **Index OUT** into a different filter or LPG - pan them left/right Now you have related but not identical timbral streams from one 10hp source. --- ## 5. Wavefolders, distortions, and nonlinear processors **Recommended types:** - wavefolder - saturator - fuzz/distortion - comparator - rectifier Specific examples: - Intellijel Bifold - Frap Tools Fold 6 - Joranalogue Fold 6 - Schlappi Interstellar Radio - Bastl Timber - various analog distortion modules ### Why Generator already produces rich, unstable tones. Folding or distortion can push it into: - industrial leads - exploding drums - harsh drones - sputtering machine textures ### Best combo Patch **Generator 2** into a wavefolder while using **Index OUT** separately as modulation or submix content. Because Generator 2 is being internally FM’d, folded results can become extremely vocal or metallic. ### Bonus idea Use a **comparator** on one of the outputs to derive a dirty gate/clock from the oscillator. That can drive envelopes that come back into Index CV for self-related rhythmic behavior. --- ## 6. Ring modulators and balanced modulators **Recommended types:** - Doepfer A-114 - Intellijel uMod II - ring mod / four-quadrant multiplier - bipolar VCA ### Why You already have two related oscillators. Ring modulation with a third oscillator or one of Generator’s own outputs produces very complex sidebands. ### Patches - Generator 1 out into ring mod input A - Generator 2 out into ring mod input B - then filter the result Or: - Generator 2 into ring mod - clean sine/triangle from another VCO into the other input - envelope the final output ### Results - bells - sci-fi alarms - inharmonic percussion - robotic voice-like tones --- ## 7. Precision oscillators as stabilizing partners **Recommended types:** - a stable analog VCO - a digital sine oscillator - through-zero capable FM source if available Specific examples: - Dixie II+ - Rubicon - STO - Ts-L - Odessa / digital clean source ### Why Generator is unstable in a good way. Pairing it with a more stable oscillator creates contrast. ### Uses - stable VCO provides tuned bass/fundamental - Generator provides upper grit and movement - stable VCO can externally FM Generator - Generator can modulate stable oscillator’s PWM/filter/folder instead of pitch ### Best musical role Use Generator as the **chaos layer**, not necessarily the tuning anchor. --- ## 8. Sequencers and gate sequencers **Recommended types:** - CV sequencer - trigger sequencer - Euclidean trigger source - random sequencer Specific examples: - Make Noise Rene - Intellijel Metropolix - Winter Modular Eloquencer - Korg SQ-1 - Pamela’s New Workout / Pro Workout - Euclidean Circles ### Why The Generator often shines more from **rhythmic modulation events** than traditional pitch sequencing. ### Better than sequencing pitch: - sequence **Index CV bursts** - sequence external FM routing changes manually between takes - sequence filter cutoff while Generator free-runs - use stepped CV to jump coarse regions ### Great performance setup - trigger sequencer → envelopes → Index CV - random/sequencer CV → one EXP input - clocked modulation → Shape This turns Generator into a percussion/texture voice that still feels composed. --- ## 9. Low-pass gates **Recommended types:** - Make Noise Optomix - LxD - Natural Gate - any vactrol-ish LPG ### Why Generator can be brash and harmonically dense. LPGs soften edges in a very satisfying way. ### Results - woody FM bongos - struck metallic plucks - Buchla-ish but dirtier transients - animated drones with natural decay ### Patch - Generator **Index OUT** → LPG → mixer - short envelope → LPG CV - another envelope → Index CV This gives a timbral transient and an amplitude transient that feel linked but distinct. --- ## 10. Delay, reverb, and granular processors **Recommended types:** - tape/dub delay - clocked delay - shimmer/plate reverb - granular texture module Specific examples: - Mimeophon - Chronoblob - Magneto - FX Aid - Desmodus Versio - Beads / Arbhar style granular ### Why Generator makes fantastic source material for spatial processing. ### Best roles - short delay for metallic resonances - long feedback delay for sci-fi dub drones - granular capture of unstable FM bursts - freeze/reverb for huge noise beds ### Patch idea Create a percussive patch with Index CV, then feed the result into: - a **very short modulated delay** for resonator-like clangs - or into **granular freeze** for shimmering alien ambience --- ## 11. Clock dividers, logic, and comparators **Recommended types:** - logic module - comparator - clock divider - PLL if you have one ### Why At low frequencies, Generator can become a strange modulation and event source. ### Uses - run one oscillator in low range as a CV/LFO - compare it to derive gates - combine with another clock source using logic - use resulting rhythmic gates to trigger envelopes back into Index CV ### Results - self-generating percussion systems - irregular clocks - machine chatter - evolving trigger ecosystems --- # Creative patch ideas ## 1. FM drum voice **Goal:** metallic tom / kick / zappy percussion ### Patch - Set **Gen 1** to **low** - Set **Gen 2** to **mid** - Patch envelope to **Index CV** - Listen to **Index OUT** - Optionally patch **Gen 2 out** into **External Input** - Set destination switch to modulate **Gen 1** This is close to the manual’s suggestion and is one of the module’s sweet spots. ### Add-ons - LPG after output for organic decay - transient shaper / VCA for punch - band-pass filter for tuned drum bodies --- ## 2. Two-layer stereo beast **Goal:** one module, wide stereo image ### Patch - Send **1** to left channel processing chain - Send **2** to right channel processing chain - Put a filter on one side, a wavefolder or LPG on the other - Modulate **Shape** slowly - Modulate **Index CV** with a different LFO/envelope ### Why it works The outputs are related but not identical. They split into beautiful stereo complexity very quickly. --- ## 3. Self-patched chaotic voice **Goal:** unstable vocal/tearing lead ### Patch - **2** → **External Input** - Set destination to **Gen 1** - Use internal FM as normal on Gen 2 - Slowly move **Shape** - Add slow CV to **Index CV** ### Result This creates a nested FM structure: - Gen 1 influences Gen 2 internally through Index - Gen 2 externally influences Gen 1 Very lively, very unstable, often vocal or shrieking. ### Add a filter A resonant low-pass or band-pass after this patch can make it much more controllable. --- ## 4. Pseudo-duophonic drone machine **Goal:** complex layered drone ### Patch - Tune Gen 1 and Gen 2 to related but not exact intervals by ear - Output **1** and **2** to separate VCAs/filters - Slow random to **Shape** - Slower triangle LFO to **Index CV** - Optional external oscillator to **External Input** routed to Gen 2 ### Add effects - stereo delay - long plate reverb - subtle saturation This gives a living drone voice with internal motion and timbral beating. --- ## 5. Audio-rate modulation hub **Goal:** use Generator as a modulation source, not the main sound ### Patch - Use **Gen 1** or **2** output to modulate: - filter cutoff FM - wavefolder symmetry - VCA amplitude at audio rates - delay time - Meanwhile use another oscillator as the audible voice ### Why Generator excels at “dirty modulation.” Its complex, shifting spectra can make ordinary modules sound far more animated. ### Especially effective targets - analog filter cutoff FM - resonance CV - wavefolder fold amount - phase modulation inputs on digital oscillators --- ## 6. Nintendo / zipper / sputter patch **Goal:** glitchy, game-like, rude noises ### Patch - Put one oscillator near the boundary between low and audio range - Put the other oscillator in mid or high - Use stepped random into one EXP input - Send envelope bursts to Index CV - Self-patch **2** into external FM for **Gen 1** - Fast manual tweaks of Shape ### Optional extras - bitcrusher - sample rate reducer - comparator for harsh gate extraction - short digital delay --- ## 7. CV laboratory patch **Goal:** Generator as dual LFO / audio-to-CV weirdness source ### Patch - Run one oscillator in low range - Use output **1** as modulation for another module - Use output **2** as audio - Use external FM to make the LFO irregular - Send the low oscillator through a comparator for gates ### Great for - weird clocking - wobbling filter motion - unstable panning - chaotic envelope triggering --- ## 8. Resonator excitation patch **Goal:** physical-model-ish textures ### Patch - Create short FM bursts with envelope to Index CV - Send output into: - resonator - Karplus/physical modeling voice - comb filter - short resonant delay ### Result The Generator makes excellent “excitation material” because it can be noisy, sharp, and spectrally rich. --- ## 9. Dirty bass stack **Goal:** tuned low-end plus mangled harmonic layer ### Patch - Use a stable VCO for the fundamental bass - Tune Generator above it - Mix Generator output quietly underneath - Envelope to Index CV for movement - Filter both together or in parallel ### Why Generator often works best in bass music as the **character layer**, not the only oscillator. --- ## 10. Envelope-following feedback patch **Goal:** dynamic self-interaction ### Patch - Generator output → distortion/filter → envelope follower - envelope follower CV → Index CV or external FM depth control - optional attenuverter in between ### Result The louder/brighter the sound gets, the more it changes itself. This can create: - snarling sustain - unstable decays - responsive noise gestures --- # Modules that pair especially well ## If you want percussion - Function generator / envelope - LPG - band-pass filter - trigger sequencer **Example chain:** Pam’s → envelope → Index CV → Generator → LPG → band-pass filter → delay --- ## If you want drones - slow random - stereo filter - reverb/delay - VCA mixer for separate outs **Example chain:** Marbles / random LFOs → Shape + Index CV → outputs split to dual filters → stereo FX --- ## If you want harsh industrial sounds - distortion - wavefolder - ring mod - aggressive filter - feedback mixer **Example chain:** Generator 2 → folder → distortion → filter Generator 1/Index Out → ring mod sidechain or feedback modulation --- ## If you want melodic use despite weak tracking - quantizer - precision adder - stable companion oscillator - tuner utility - sequencer with lots of attenuation control ### Important note Because it does **not** track 1V/oct properly, use it for: - approximate intervals by ear - drones - riffs in a limited register - layered textures over a tuned voice Don’t expect it to behave like a precision FM voice. --- # Performance tips ## 1. Treat Shape as the macro knob If you only touch one parameter live, make it **Shape**. It changes both oscillators and often gives the biggest “scene change.” ## 2. Use the Index knob carefully Per the manual: - **full left = 100% gain** - **full right = 0% gain** That’s easy to misread in performance. It behaves “backwards” compared to some expectations. ## 3. Separate “sound” and “animation” A nice workflow: - set base tone with ranges + fine tuning - set Shape to taste - use Index CV for animation - use external FM only as spice ## 4. Exploit the two outputs independently Even if you think of it as one voice, it is often more rewarding as: - one raw output - one processed output - one center image, one side image - one audio source, one modulation source --- # Summary The Generator is best understood not as a polite dual VCO, but as a **compact analog FM ecosystem**. It rewards: - envelopes into **Index CV** - self-patching through **External Input** - random and slow CV into **Shape** - splitting its multiple outputs into separate signal paths - pairing with **filters, LPGs, VCAs, wavefolders, and time-based effects** If you want the most immediate wins, pair it with: 1. **Function generator/envelope** 2. **LPG or character filter** 3. **Random source** 4. **VCA/attenuverter utility** 5. **Delay/reverb** That combination turns Generator into a monster for: - metallic percussion - unstable drones - noisy basses - glitch effects - chaotic modulation [Generated With Eurorack Processor](https://github.com/nstarke/eurorack-processor)