PWM Malevolent

PWM Malevolent synthesizer review


My initial impression of the Malevolent was a bit of a car crash. I couldn’t get any sound out, couldn’t find what it was I needed to do. This was all during a live stream, so there was all sorts of pressure to get it playing, and I couldn’t seem to see the synth through the field of knobs. But then that’s the whole vibe. I’m not saying that Malevolent was designed to frustrate the heck out of you, but rather it’s not the least bit concerned with how you feel about it.

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The layout is, shall we say, unconventional? It has all the familiar parts you expect to see but not where you expect to find them. If you play the keyboard, the “Keyboard” light will flash, and the Envelope LEDs will light up, but you won’t necessarily get any sound. The envelopes are directly below the VCOs, rather than near the VCA, which is odd. But then, where is the VCA? Each VCO has its own level control, but they are not in the Mixer section, where you might expect to find them on any other synth. So, to persuade Malevolent to make a sound, you’ve got to stumble across at least one of the two VCO level knobs, engage one of the waveform buttons, make sure you’ve turned up the filter cutoff and then find the VCA. It does exist, but it’s in an unnamed section with two knobs labelled AM1 and AM2. Turning up the AM1 knob routes Envelope 2 (of course) to the VCA, which finally rewards you with a blip. It all makes some kind of sense once you know.

PWM Malevolent
PWM Malevolent

My last gripe about the workflow is that with Malevolent sitting on my desk in a comfortable playing position, I can’t see any of the knob labels; they are all obscured by the very tall knobs. I have to lean forward almost over the top of the synth to see what anything is. It’s not an uncommon problem, but that makes it no less annoying.

Right, so while I’m feeling suitably miffed, let’s get into this pretty darn awesome little fidget bunny of a synthesizer.


This, is a banshee, a wailing hell demon of indeterminant origin, a squealing monster that wants to eat your face and smear itself with your remains. Is that a bit over the top? Maybe but this synth has some balls. There’s stuff going on in here that I’m not sure should be, and whenever I try to fix it, it just takes me off on some other adventure into a pit of crackle-humping fizz swizzling.

Two oscillators are always more fun than one, and these two are spoiling for a fight. While you can dial in some super nice detuned movement, Malevolent wants to push it over the edge at any given moment. It’s like everything is conspiring to overdrive, over-ripen and lose its shape into fizz, goo and sparkiness. This is no Grandmother, Monologue or ARP; this finds its heritage in the Wasp, MS-20 and OSCar. Maybe there’s something quintessentially British about a synth that feels like it’s about to fall apart (sonically, not physically).

You’ve got a mix of unruly and strangely shaped waveforms running at levels on that push the tone into unusual places while the resonance circuit just wants to dive bomb to destruction.

This is a lot of fun.

Here’s my extended sound demo video to experience it for yourself.


Malevolent is an all-analogue, dual-oscillator, semi-modular synthesizer. The analogue circuitry is designed by Future Sound Systems, which is known for making machines that ooze with overdriven warmth and drip with saturated grit. Their character is all over this thing. Each oscillator has three switchable waveforms with individual and mixed outputs.

All of them can be Shaped in a pulse-width modulation style, not just the square. The Shaping is quite different from other waveform squashing I’ve come across. There’s something in the centre position that wants to flip the waveform over. As you you dial through the shape, you get some nice smooth movement and then it flips and gives you a slightly different movement on the other side. It’s as if your shaping ends up tearing the waveform. As you modulate, you get this sort of throbbing as it passes the midpoint. Maybe this is all part of the character design, or maybe it’s just how the PWM works, but it certainly brings in more edginess because it doesn’t have enough of that already.

The level control on the VCOs seems to go up to about 13. You can find the cleanest level at about the 3 o’clock mark. Anything after that pushes it into overdrive. So if you are looking for good behaviour, then take the edge down on the oscillator level.

PWM Malevolent
PWM Malevolent

The filter is a 2-pole multi-mode filter with low, high and bandpass outputs. When using it unpatched, you only get to use the raucous low pass filter (this is easily remedied). The self-oscillation is ridiculous and starts going off long before you even reach 12 o’clock on the resonance knob. There’s an interesting interplay between the filter resonance and the oscillator levels. The resonance wants to push its sine waves into any available gap in the waveform. As you push up the oscillator it squeezes out more of the resonance, overwhelming it with overdrive. Then as you dial back the squealing filter comes back in. There are a lot of things in play here and it all enjoys a good bit of motion.

There’s a single LFO with triangle and square wave outputs for modulation. The triangle wave is normalled to the FM2 knob destinations when unpatched and so to use the square wave you’ll have to dog out a patch cable. There are two envelopes where Env 2 is dedicated to the VCA whereas Env 1 is normalled to the FM1 knob destinations. So without any patching, the LFO and Env 1 is routed to the pitch of each VCO and the cutoff of the filter via the FM1 and FM2 knobs. The VCA gets Env 2 on the AM1 knob and the LFO on AM2. This is all before you do any patching. Got it?


The keyboard is a nice thing to have, and even though it’s minikeys it doesn’t feel too bad. It’s is connected to the pitch control on the oscillators and gate control on the envelopes, as you’d expect. There is velocity, and there’s a patch socket to use it on something, but it’s not patched to anything by default. It has an arpeggiator which is nice, if a bit mystical to start with because there’s no documentation on it. But once you work out that you have to click the joystick to enable latch mode and then pull down to enable Hold, things start going a bit more smoothly. While holding the Arp button, you can move the joystick to select one of 6 Arp modes, although there’s nothing to tell you exactly what is selecting which. There’s also a Vibrato button which switches the pitch bend left/right joystick to function as a push-to-mod wheel, or rather a Roland modulation style function when you push the joystick forward. I’m not sure why the pitch-bend and vibrato need to be separate. It’s not unusual to have pitch on the X-axis and modulation on the Y-axis in these sorts of control systems.

PWM hasn’t gone in for much in terms of documentation. There’s a Quick-Start guide which would have saved my live stream embarrassment had I seen it, but it’s really basic. On the website you’ll find a small number of short videos which go through a single feature each. These are helpful; for example, a 30-second video on Glide just told me that pushing forward on the joystick enables Glide or portamento between notes which is why it can’t be used for Vibrato at the same time. But would it kill them just to write out a list of functions in a manual with maybe a diagram or two?


With the semi-modular normalisation, you’ve got a solid synth architecture going on, but you can break all those connections with the canny use of patch cables. So, for instance, the LFO has both a triangle and square wave, but only the triangle is tied to anything internally. Plug a patch cable into the square output, and you can plug that into the filter, or pitch control, shaping or VCA. This instantly expands on the possibilities the synth presents itself with.

Patching also gets you into the other modes of the filter. By default, you get the juicy lowpass filter, but you can patch the Mix Out of the Mixer directly into the Bandpass or High pass filter.

PWM Malevolent
PWM Malevolent

What I like about the VCOs is that they can operate as complete Eurorack VCO modules. I think they were designed this way. You have individual outputs on each waveform plus the mix output. You’ve then for 1v/oct inputs, FM inputs and CV control over the wave shaping. You can patch these from your modular and have them fully and independently integrated. You can do the same with the envelopes, the filter and LFO. It’s very much at home in a modular environment. I wonder if they considered letting the front panel come off so it can be dropped into Eurorack. It seems just slightly too big.

You can, of course, patch two different sequences into the VCOs from an external sequencer and have them play independently. They would run through the same filter unless you patch one VCO to another filter module elsewhere. This versatility really gives it another edge and another opportunity to do something different.


I should mention MIDI, although I’ve not used it this way. But PWM has gone to great lengths to make sure the MIDI is implemented separately and comprehensively. You can use the MIDI ports on the back or USB into your computer for full MIDI control over the synth. The keyboard can be a MIDI controller and a MIDI-to-CV interface. Exciting stuff if that’s your bag.


Malevolent has a quite unique ability to fall apart at every turn. It will surprise you, spit at you and then let you fiddle the life out of its dying overtones. It’s enormous fun and keeps pulling you into the fight as you tag-team your way to another disastrous patch of awesomeness.

There are some workflow annoyances, and it has an uncanny ability to lose itself or become so twisted that you can’t work out how to get it back from the brink. A little more explanation would help keep things together.

But those are small things compared to the juiciness that’s on offer and the fun you could be having. And you could use it as a row of modular in an existing setup if you wanted. At around £450 for a dual oscillator synth with a heart of fierce tones, you are faced with a decision between this and the Korg MS-20 mini. That’s a tough one, but it also shows how great Malevolent really is.

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