Sequencing & Clock

Clock

The master clock — the metronome that drives every tempo-aware module in a patch.

What is a Clock?

A clock generator is the heartbeat of a modular patch. It produces a steady stream of gate pulses at a tempo you set in BPM (beats per minute), and every other timing-aware module in the rack — sequencers, envelopes, LFOs, drum voices, Euclidean rhythm generators — listens to that pulse and acts in time. Without a clock, a patch is a drone. With one, it has a beat.

Mechanically a clock module is a phase accumulator: a counter that ticks forward by a small amount every audio sample, wraps around once it reaches the end of one beat, and emits a gate high for the first part of each beat and a gate low for the rest. The rate you choose (120 BPM = 2 Hz, two beats per second) determines how fast it ticks; the pulse width determines how much of each beat the gate stays high.

Most clocks expose more than one output. The main clock runs at the set BPM. Division outputs (/2, /4, /8) fire at related but slower rates and exist so a single module can drive a fast hi-hat lane and a slow bassline lane from the same tempo grid. A reset trigger fires when the clock starts, so sequencers and clock dividers can sync to step 1 instead of mid-pattern.

Our Clock

Our Clock is a 6 HP master tempo source. BPM runs from 20 to 300 covering every musical context from glacial ambient to drum & bass. The main CLK output is joined by /2, /4, /8 divisions and a dedicated reset trigger that fires on every Run-toggle transition.

Timing precision is well below one millisecond — jitter is essentially nonexistent across the full BPM range, so even fast tempos stay rock-solid. The pulse width knob (0.1 to 0.9) reshapes every output simultaneously, including the divisions, so a short staccato setting cascades cleanly through the whole patch.

Think of it as the simplest possible source of truth: one BPM, one Run switch, one pulse-width knob, four sync-locked outputs. For more elaborate clocking schemes — independent multipliers, polyrhythmic ratios per output — pair it with a Clk Div.

In a patch

A clock typically goes everywhere. Its main output drives a step sequencer (advancing one note per beat), an Euclidean generator (firing rhythmic patterns), and an ADSR (gating notes on and off). The reset output goes to anything that needs to sync to step 1. Division outputs go to slower modulators or secondary rhythmic voices.

When you want even more rhythmic flexibility, the clock feeds a clock divider whose four outputs each run at a different ratio of the master tempo. That is the standard way to build polyrhythmic patches: one tempo source, many derived tempos. For free-running modulation (no tempo grid, just a slow wobble) you'd use an LFO instead.

Outputs

CLK (gate) — Main clock output. Fires a gate pulse at (BPM x Rate) per minute. This is the primary tempo source for your patch.
RST (gate) — Reset trigger. Fires a single pulse when the clock starts running. Useful for resetting sequencers to step 1.
/2 (gate) — Fires once every 2 CLK pulses with the same gate width as CLK. At Rate=1 PPQ + 120 BPM, one pulse per second. Use for slow envelope triggers or to gate every other note.
/4 (gate) — Fires once every 4 CLK pulses with the same gate width as CLK. At Rate=1 PPQ + 120 BPM, one pulse every 2 seconds. Great for downbeat accents or slow modulation envelopes.
/8 (gate) — Fires once every 8 CLK pulses with the same gate width as CLK. At Rate=1 PPQ + 120 BPM, one pulse every 4 seconds. Useful for very slow filter sweeps or pad-style envelopes.
/16 (gate) — Fires once every 16 CLK pulses with the same gate width as CLK. At Rate=1 PPQ + 120 BPM, one pulse every 8 seconds. With Rate=4 PPQ this lands on the bar line in 4/4 - useful for structural accents, slow modulation cycles, and evolving pad envelopes.

Controls

BPM — Tempo in beats per minute, from 20 (very slow) to 300 (very fast). 120 BPM is a good starting point for most music.
Run — Start/stop toggle. When off, no pulses are sent. Turning it on resets the phase and emits a reset trigger.
PW — Pulse width - how long each gate stays high as a fraction of one CLK pulse period. 0.5 means the gate is high for half the period. Lower values give short staccato triggers, higher values give longer sustained gates.
Rate — Pulses per quarter note (PPQ). 1 = one pulse per beat. 2 = 8th notes. 4 = 16th notes - the canonical choice when chaining into SEQ8 or Euclidean if you want a DAW-like step-sequencer feel at the same BPM. 8 = 32nds for hi-hats and trills. The dividers (/2, /4, /8, /16) divide the active CLK rate, not raw BPM.

Inspired by

A classic master clock topology — BPM-set tempo with main clock plus /2, /4, /8 division outputs and a reset trigger on start. The sub-sample-accurate phase accumulator and zero-jitter division are contemporary, but the layout (BPM, run, pulse width, divisions) is the canonical Eurorack clock.

ALM Pamela's Workout
Make Noise Tempi
classic master clock topology

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