The Moog Grandmother becomes much more powerful once you start thinking in terms of patching. Below is every connection with a simple, real-world use case so you can immediately try things out.
Keyboard & Performance Outputs
Gate Out
Outputs voltage as long as you hold down a key.
Use case: Patch Gate Out → Sync In to restart LFO waveforms with each key press.
KB Out
Sends voltage based on which key you press.
Use case: Patch to PWM In to change pulse width based on keys you’re pressing.
KB Vel Out
Outputs voltage based on how hard you play.
Use case: Patch to VCA Amt In for velocity-sensitive volume.
LFO & Modulation
Rate In
Controls the speed of the LFO via voltage.
Use case: Patch KB Out → Rate In so higher notes produce faster modulation.
Sync In
Resets the LFO waveform when it receives a signal.
Use case: Gate Out → Sync In so every note starts the LFO at the same point.
S/H Out
Random stepped voltages.
Use case: Patch to Cutoff In for random filter movement.
Modulation Wave Out
Outputs the LFO signal.
Use case: Send to Mult, then route to Pitch In + Cutoff In for layered modulation.
Oscillator Section
Wave Out (Oscillators)
Outputs raw oscillator signals.
Use case: Send Osc 1 → external effect or separate filter path.
Pitch In
Controls oscillator pitch via voltage.
Use case: Patch Envelope Out → Pitch In for pitch envelopes (classic synth pluck).
PWM In
Controls pulse width.
Use case: Patch LFO → PWM In for evolving, animated timbre.
Lin FM In
Linear frequency modulation input.
Use case: Patch audio-rate Osc 2 → Lin FM In for metallic FM tones.
Mixer & Routing
Osc In + Noise In
Lets you inject external signals into the mixer.
Use case: Patch CV like LFO or envelope to mix control voltage instead of audio (you have to bypass the audio signal from the osc directly to the filter).
Mixer Out
Outputs the mixed signal without breaking internal routing.
Use case: Route Mixer Out → Oscillator input for feedback/overdrive patches.
Mult
Splits or combines signals.
Use case: Duplicate one LFO to control filter, pitch, and PWM at the same time.
Can also be used to „merge“ audio signal but only from OSC Wave Outs, Mixer Out and the Filter Outs.
Filtering & Tone Shaping
High Pass In / Out
Adds a high-pass filter into the chain.
Use case: Combine with low-pass to create a band-pass effect.
Attenuator In / Out
Controls signal strength or if nothing is patched into the input the output sends fixed voltage.
Use case: Send Attenuator Out → Cutoff In to manually dial in a constant offset.
Filter In
Routes signal into the filter and breaks internal routing from the mixer out.
Use case: Process only one oscillator through the filter for layered textures.
Cutoff In
Controls filter cutoff via voltage.
Use case: Patch LFO → Cutoff In for classic filter sweeps.
Env In
Controls how much the envelope affects the filter.
Use case: Use attenuated voltage to fine-tune envelope intensity dynamically.
Filter Out
Outputs the filtered signal.
Use case: Send to external effects or back into the mixer for overload feedback patch.
Envelope & Modulation
Trigger In
Triggers the envelope externally.
Use case: Patch LFO → Trigger In for rhythmic pulsing without playing keys.
Env Out (+)
Normal envelope output.
Use case: Patch to pitch in of Osc2 in hard sync for nice timbre sweeps.
Env Out (-)
Inverted envelope.
Use case: Patch to pitch in of Osc2 in hard sync for nice timbre sweeps (just reversed direction)
VCA & Amplitude
VCA Amt In
Controls volume via voltage.
Use case: Patch LFO → VCA Amt In for tremolo effects.
VCA In
Final signal input before reverb.
Use case: Often used when patching the filter in a different order and sending the combine signal from the mult into VCA to get the signal back into the chain.
Reverb In
Routes signals directly into the reverb, breaking normal routing.
Use case: Send only noise or one oscillator into reverb for layered ambience.
Sequencer & Clock
Clock Out
Sends tempo signal.
Use case: Sync external drum machines or modular gear.
Clock In
Receives tempo signal.
Use case: Sync the Grandmother to external sequencer.
Reset In
Resets sequencer position.
Use case: Keep multiple sequencers aligned in a live setup.
On/Off In
Starts/stops sequencer.
Use case: Control playback from an external trigger source or modular system.
Final Thought
Once you start combining these use cases, the Moog Grandmother really opens up. The real magic happens when a single signal (like an LFO or envelope) is split and reused across multiple destinations to create complex, evolving patches.
If you want to learn how to use the semi-modular connections in-depth watch a free lesson of the full Moog Grandmother Course:
https://synthskool.com/courses/moog-grandmother-course/