I’ve never owned a Casio CZ, nor any hardware instrument for that matter. I’m afraid I just can’t afford it. Perhaps if I had set out on my musical journey twenty years earlier in the mid-eighties, when everyone was ditching their analogue gear under the foolish notion that digital was superior in every way. Back then, you could swoop down and scoop up analogue equipment for next to nothing, but those days are long gone. Today, vintage analogue hardware is a highly sought after commodity.

That being said, throughout the seventies and early eighties, analog circuitry wasn’t cheap even then. The cost of manual labor and supplies (many of which became scarce overnight) was a problem for engineers and potential investors who couldn’t afford to mass produce something so dependent on labor and finite resources, and even if they could, the average retail customer was certainly in no position to shell out several hundreds or even thousands on a musical instrument.

A Brief History Lesson

The original CZ line was unabashedly digital. Casio’s CZ-101, released in November of 1984, was one of the first affordable polyphonic synthesizers made available on the retail market. Just a year after the Yamaha DX7 had blown us all away with the advent of phase modulation, yet another Japanese company more commonly known for manufacturing calculators and wristwatches introduced the world to phase distortion, one of the biggest game changers in the history of modern synthesis.

What made the CZ-101 so affordable is that (similar to frequency modulation) phase distortion synthesis eliminates the need for filters, which often require expensive analogue components. Of course, other reasonable compromises were made to fit the CZ-101 within a tight budget, such as smaller “miniature” keys offering only four octaves instead of five. However, its small size only made it all the more easier to travel with, making it perfect for gigging synthesists.

But what really made the CZ-101 so special is the way you could use its eight-stage envelope generator to apply phase distortion to completely digital waveforms in real time, producing a far more rich, warm sound than that of Yamaha’s evermore popular DX synths, which were notably more harsh in comparison due to the fact that the DX7 used only pure sine waves, whereas the CZ-101 did the reverse opposite, providing eight digital waveforms including the usual Saw, Square, Pulse, and then some very unusual waveforms like Double-Sine, Saw/Pulse, and three unique Resonant waveforms.

Of course, when I first fired up Plugin Boutique’s software emulation of Casio’s entire CZ product line, from the CZ-101 to the CZ-5000, I was a little off-put by the complete absence of a sine wave, mainly because I’ve never owned or even used any of the CZ line, plus I didn’t fully understand how phase distortion works.

So, What Is Phase Distortion Anyway?

Long story short, phase distortion takes place within a “single cycle”, having more to do with the amount of “phase accumulation” within the duration of each individual cycle. Every waveform begins and ends its cycle at specific phase values anywhere between bipolar integers of one… rinse and repeat. When you increase the pitch of a waveform, its cycle speeds up, and when you decrease the pitch, it slows down. Simple, right? Phase distortion is what happens when you speed the cycle up and then slow it down just so that you neither exceed or fall behind the “sample rate”, which is basically the rate a complete cycle would normally traverse if it were never sped up or slowed down at all. This is how phase distortion seamlessly alters the shape of a waveform within a fraction of a second. No filters. No wavetables. Just math.

Once I finally understood this, I realized that each of VirtualCZ’s eight digital waveforms are actually sine waves with a mathematical solution applied to the phase accumulator when the amount of phase distortion is set to its maximum value. Just load up any of these eight waveforms and decrease the “Depth” fader in the DCW (Digitally Controlled Waveform) Envelope Generator and… lo and behold… a sine wave is born!

The Review

Upon startup, I was a little overwhelmed by its slightly counter-intuitive interface, but one very important thing to keep in mind is that VirtualCZ was made to be far more than just a virtual instrument, but also a SYSEX editor intended for owners of the original hardware. So, it’s very important that the control surface and its internal architecture reflect that of the original instrument. But don’t worry, once you begin to understand how things work, it’s totally worth your time and energy getting to know VirtualCZ. Plus, if you employ the use of a good virtual oscilloscope, you will learn to program it evermore efficiently.

The first thing I started looking around for was a global control for phase distortion, which I didn’t see right away, but shortly after referencing the manual, I realized there are actually ten controls (for each “Line”) that determine the amount of phase distortion, nine of them being in the DCW envelope, and the other in the main “OSC” section labeled “DCW”, which is a grey knob below the two yellow rectangular buttons in each of the two “Lines”, but I’ll get to those later. If you start with the factory “Initialize” patch, you might notice that the DCW knob has no effect when you turn it from left-to-right, but that’s because the Depth knob in the DCW envelope is turned all the way up. If you turn it down to zero, like I mentioned earlier, the waveform will eventually become a sine wave. Now, turn up the DCW knob in the OSC section. Voila, phase distortion! This is a great way to program sounds in VirtualCZ with the use of a signal analyzer in order to fine tune harmonic content before you start messing around with the Multi-Segment Envelopes.

But let’s get back to those aforementioned “Lines”. Each of the two Lines offer two completely separate oscillators with eight “Line Shapes” that can be mixed, detuned or modulated either with Ring Modulation (which multiplies the first Line’s output by itself or by the second Line’s output) or a Noise generator applied to the pitch of the second Line. The ring modulation is especially useful when designing long evolving pad sounds, or more typically, harsh inharmonic overtones and dissonant bells and chimes.

Okay, now let’s roll up our sleeves and dig into those big bad Multi-Segment Envelope Generators! Obviously, there are two horizontal rows for each Line with three categories: “PITCH”, “DCW” and “AMP”, with up to eight stages, all of which can be incredibly fast or slow, steep or shallow – but one of the most confusing things about these envelopes are the buttons in the top left and right-hand corners intended for assigning the “Sustain Step” and the “End Step”, which are basically the sustain and release stages of the envelope. It’s not very complicated. Just make sure to set the End Step before you set the Sustain Step, because you might accidentally overlap the Sustain Step if you set it on a later stage than the End Step.

Another thing: Remember when I said there are ten controls that determine the amount of phase distortion, nine of them being in the DCW envelope? As I pointed out, the DCW knob in the OSC Section is one of them, and the Depth knob in the DCW envelope is another, but the Level faders for each stage in the DCW envelope are the remaining eight, with special emphasis on the Sustain Step, which just so happens to be the first (“DEG1”) Level fader upon loading the Initialize patch. Also, there’s a “Loop Enable” button that will loop each individual envelope, and yet another nifty little button near the bottom right-hand side of the screen that will enable “ADSR” mode, just in case you’re not in the mood to fuss with the MSEG controls. Of course, some sounds don’t require the use of MSEGs, so you can program them very quickly that way.

Sadly, there is no polyphonic unison, but as I explained earlier, it’s important that VirtualCZ’s internal architecture is identical to the original in order to create functional SYSEX patches, so it doesn’t really make much sense to give VirtualCZ additional functionality that can’t be translated to it’s corresponding hardware. That being said, there are eight voices of unison for “Mono” and “Legato” modes, with a “Portamento Time” parameter and a “Width” knob, panning each unison voice apart in the stereo field. Of course, in “Polyphony” mode, the Width knob pans each individual note left-to-right arbitrarily.

The “Scaling” section took me by surprise. Each of the two-dimensional tables have a drawable curve with a unique character similar to that of an “Etch-A-Sketch”, allowing you to create some bizarre shapes and behaviors for aftertouch and velocity sensitivity. You can even dial in the depth of sensitivity for aftertouch routing within the “Aftertouch Target” window for “LFO”, “AMP” and “DCW”.

The Verdict

I think this needs to be said, so I’m just gonna say it… VirtualCZ is not a power synth, at least not by today’s standards, but it is capable of making some beautiful sounds! I usually turn my nose up at “emu” synths, mainly due to the very plain fact that today’s softsynths are leaps and bounds and backflips in the air more powerful than any vintage synthesizer could ever hope to be, and also because emus are often poorly designed. But in this rare case, even though I’ve never owned a CZ product, I feel very comfortable in my assessment that developer Oli Larkin has successfully reproduced the magic of the original instrument.

I’m afraid there’s just no other way to put it: VirtualCZ has “it”… that special something you just have to experience for yourself. It’s not the most powerful thing on the planet, but it was never intended to be. Sure, owners of the original CZ line will no doubt be thrilled, but I’m more than certain that VirtualCZ will inevitably stir up a renewed interest in phase distortion synthesis, which is long overdue.

More info: VirtualCZ ($99)

The Giveaway

We are giving away one copy of VirtualCZ, kindly provided by Pluginboutique for BPB readers. To enter the giveaway, simply leave a comment on this article. Only one entry per person is allowed. The winner will be picked using a random number draw and announced on this page on May 27th.

The giveaway is now closed! The lucky winner (as selected by the random number generator) is our reader Michael (m******.s**** who left the 153rd comment on this page. Congrats! :)

Thanks everyone for joining in and following BPB. We have another awesome giveaway coming up in the next couple of days, so stay tuned!

VirtualCZ Review


VirtualCZ has that special something you just have to experience for yourself. It’s not the most powerful thing on the planet, but it was never intended to be. Sure, owners of the original CZ line will no doubt be thrilled, but I’m more than certain that VirtualCZ will inevitably stir up a renewed interest in phase distortion synthesis, which is long overdue.

  • Features
  • Sound
  • Workflow
  • Stability
  • Design
  • Pricing
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About Author

Bryan Lake is a sound designer and a musician. He publishes sound design tutorials and sound libraries on his website Sound Author.


  1. mitch mitchell


    Used to own an original CZ101 years ago and mistakenly got rid of it ( bought it secondhand from turnkey Music. cost me the grand sum of £100 ) still miss that lovely little keyboard .. always wanted to get another someday hopefully i might be in with a chance with the Vst give away .. Good luck anyway with all taking part

  2. CZ101, my first synth back in the 80s . Another reason to get it back then was that Casio implemented MIDI as standard. And that was less common. So later with a primitive Atari sequence, a 4 track cassette recorder, and a lot of patience. You could layer tracks to cassette from the same keyboard, and feel like a God. ! Got some very pleasant noises from the CZ101.

  3. Candle Nine


    Saw this a while ago on Plugin Boutique and was intrigued. Glad to see it lives up to expectations.

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