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Rebel Technology Phoreo

Eurorack Clock, Gate & Trigger Processor By Paul Nagle
Published August 2016

Rebel Technology’s Phoreo [Rendering its name in Greek will break the SOS publishing software — Ed] is a clock, gate and trigger processor for the aspiring sequencer wizard. It provides pulse-width control of clock or trigger signals, can act as a clock multiplier and will spit out repeated notes to order. A snug little module, Phoreo squeezes six chunky knobs into a mere 10hp and gives each function an individual input, output and CV control. Swirly graphics tie together the CV inputs and relevant attenuator knobs, and a pair of yellow LEDs indicate the pulse width and number of repetitions.Rebel Technology Phoreo

The inputs are normalised from the top downwards, so a single connection at the Mod input can feed the rest if necessary. The top left-hand knob controls the pulse width over its full range of 0 to 100 percent — or from extreme staccato to legato. When applied to gate length, this is an instant tool for changing the feel of an otherwise static sequencer pattern, one that is taken to a new level under CV control. Simply plumb in a slow LFO and your patterns gain all manner of slurs, slides and unexpected changes of emphasis. (You should ensure Phoreo’s output is driving an envelope with a sustain stage to exploit this behaviour.) The technique is equally applicable to percussion modules — providing they respond to gate time — and it offers a source of wacky unpredictability when used to process the gate output of an analogue synth.

Progressing downwards, Mul applies a multiplication factor to an incoming clock or series of triggers, up to a manic 16x. Phoreo calculates the new rate based on the last two incoming pulses, and should you happen to have a keyboard’s gate output connected, you can set the speed directly, tap-tempo style. It’s also well worth trying to fool the calculator by sending a few random triggers — this can result in some cool flams and stutters. However you achieve the desired multiplication, the clock output will continue even after you disconnect the source: it’s overriden only when fresh trigger input is received.

The most obvious use for multiplication is in clock doubling, trebling, etc, or perhaps for producing a synchronised clock based on a loose LFO source. Knobs are maybe not the ultimate selector for so many discrete values though, especially as the rotation passes smoothly through them all. It’s inevitable that you’ll occasionally fall foul of a sneaky triplet or a more unusual division, which could prove awkward when using Phoreo as a clock source, particularly in a live environment. To restrict the output to ‘normal’ divisions, it’s far better to employ the CV input, preparing only the desired multiplications in advance. One way to do this would be using the discrete values available to a step sequencer.

Since I couldn’t always hear the difference between the highest multiplication factors (at least at regular tempi), I asked Rebel Technology whether there was a preferred rate for incoming pulses. Apparently, Phoreo can cope with anything from half a millisecond to 18 hours! It’s even possible to feed it audio (up to 20kHz) which is translated into square-wave overtones that glitch like a possessed Space Invaders machine!

The final function is repetition, with the Rep knob dialling in up to 16 repeats that run at the multiplier’s clock rate. Repeats are vital for sequencer ratchetting or flashy, echo-type effects, and whenever you need fills, thrills or high-speed, pneumatic trills, Phoreo can be the solution.

One thing to be aware of is that this module requires a +5V power supply. If you have one of the older Doepfer cases (as I do), you’ll therefore have to invest in one of the available solutions. I opted for the Mutable Instruments Volts (around £20$20), which fits easily into a unused power connector and delivers 1.5A.

Phoreo is a deceptively simple module that would be an asset in any moderate to large sequencing environment. It’s also a great way to add sophistication to a basic sequencer. Its features hang together neatly and the act of combining them under tasteful voltage control yields dividends every time.