Mutable Instruments Edges User Manual

Mutable Instruments | Edges

Edges is a bank of four voltage-controlled digital oscillators - 3x square wave channels and 1x LFSR noise
or triangle channel - an architecture inspired by the music synthesis circuitry of classic 8-bit consoles and
home computers. For a more faithful reproduction of these classic sounds, the square waves are
generated using digital logic (timers / counters) rather than DSP techniques, and are thus free of aliasing
artifacts. Each voice is equipped with a gate input, allowing it to be toggled on/off without the need for an
external VCA. The 4 channels have individual outputs and are sent to a built-in mixer. Finally, a simple
polyphonic sequencer allows each channel to play arpeggios or trills.

Edges is designed for Eurorack synthesizer systems and occupies 20 HP of space. It requires a -12V /
+12V / +5V supply (2x8 connector), consuming 25mA from the -12V / +12V rails and 45mA from the +5V
rail. The red stripe of the ribbon cable must be oriented on the same side as the “Red stripe” marking on
the printed circuit board.

A1 .. A4. GATE: Channel gate input. When the sequencer is off, this input acts as a binary VCA - the

channel is off when the signal is 0V; on when the signal exceeds a 0.7V threshold. When the sequencer is
active, the channel is always on, and this input acts as a clock input, to step through the sequence. The
gate inputs are normalled. For example, if you connect a jack on channel 2’s gate, it will be used for

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Mutable Instruments | Edges

channels 3 and 4 unless a jack is connected in one of their gate inputs.

B1 .. B4. V/OCT: Channel frequency input. Just like the GATE inputs, these are also normalled across all

channels. This can be used, for example, to transpose a chord or polyphonic sequence from a single note
CV.

C1 .. C4. MOD: Channel frequency modulation input. This input serves the same purpose as the V/OCT

input (and is summed to it); but is not normalled from one channel to the other.

D1 .. D4. FREQ: Channel frequency control, spanning 6 octaves.

E1 .. E3. XMOD: This switch enables a special digital cross-modulation effect. From top to bottom:

Channel 1 to Channel 2 hard sync.1.
Channel 1 x Channel 2 ring modulation.2.
Channel 1 x Channel 3 ring modulation.3.

F1 .. F4. OUT: Channel individual output. When a jack is plugged in this output, the corresponding

channel is removed from the global mix.

G1 .. G4: Channel volume control, for the mixer. Not that this potentiometer does not affect the individual

outputs’ levels (they are always at full level).

H. MIX: Mixer output.

I. WAVEFORM SELECT: Press these switches to cycle through the various waveshapes available on

each channel. Hold a switch to modify the quantization/sequencing/calibration options of the
corresponding channel (see the “Channel options” section).

LED 1..4: They indicate the status of each channel’s gate input.

For channel 1, 2, and 3, the waveshapes are all square waves with 50%, 66%, 75%, 87%, 95% pulse or
CV controlled pulse width. With this last option, channel 4’s frequency input doubles as a PWM control.

For channel 4, the waveshapes are sine, triangle, NES triangle (with 16 loudness levels), sample-and-hold
noise, NES LSFR 1 (long cycle) and NES LSFR 2 (short cycle). LSFRs are linear feedback shift registers ­a digital technique for creating cyclic noise patterns.

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