An edited version of this text also appears in
SOUND ON SOUND magazine Vol.13 No.1. November 1997

Review by Chris Carter


The FAT Procoder PCP330 is a new vocoder from the same stable as the Freebase MIDI 303 clone. Except this is an all analogue device with no MIDI or digital trickery and the technical specifications, while not up there with pro spec models, is nevertheless pretty impressive. It uses an 11-band voicing system that can also be pushed into service as a filter-bank and in keeping with analogue philosophy there are separate controls for each function, 19 knobs on the front and 2 variable pre-sets on the rear. Eleven of the knobs are vocoder/filter level controls and the rest are for adjusting the input and output levels. Interfacing with the outside world is handled by three 1/4" jack inputs, an XLR microphone input and a single mono 1/4" jack output. The 19" X 7" rack mounting aluminium case is very light and power is supplied by a chunky wall wart PSU (see box).

If you haven't come across a vocoder before let me briefly explain a little about how the process works. At its most basic the concept is a little like a ring modulator, the vocoder takes two different input signals and makes a third signal that is derived from combining the two. A vocoder does this by

analysing the input sources and using analysis and synthesis circuits to control banks of filters and VCA's (11 of each in this case). The affect of this is to superimpose the characteristics of one signal, usually a voice, over the other signal, usually an instrument. The end result is that instantly recognisable robot voice or talking guitar sound.

To get the PCP330 up and running is pretty painless, partly because it has an internal sawtooth oscillator (or sawtoot, as the manual insists on calling it). It's a basic affair with a range from 15Hz to 600Hz and although it 's referred to as a VCO the oscillator can only be swept manually and can't be controlled by an external VC keyboard signal or an LFO etc., shame. To produce a vocoded sound all you need is a mic or line level signal plugged into one of the ANALYSE (modulator) inputs. If the Modulator and Carrier level controls are set approximately mid-way and all the vocoder and filter level controls are set to maximum, which I suppose could be regarded as a default setting, you can hear that familiar vocoder sound.

I've always thought vocoders sound a lot more interesting when they're not used with a microphone, you know that totally cliched voice box sound. However I may be in a minority here, especially with the current 'sounds of the seventies' revival. But I'm going to stick to my guns and for this review I only used a mic a couple of times, and that was to check that the XLR socket worked as it should and it does, with plenty of gain available, if needed, via the input level control. To keep the audio signal as clean as possible there are a couple of peak reading LEDs and a compressor on the inputs to help prevent overdrive and a noise gate on the outputs to keep the noise floor low.

Apart from all the usual features you would expect to find on a vocoder, such as separate output mix levels for the Modulator, Carrier and Vocoder signals there is also a Sibilance level control. This knob (plus two small pre-sets on the rear, to adjust for mic or line level) controls a sub-section of the vocoder called the VUD or the Voiced-Unvoiced Detector. This circuit is used to detect any sibilant content in the carrier signal (the mic/line input) and when it does to superimpose a non-harmonic noise signal over the harmonic vocoder sound. This feature would normally be used with a microphone and voice and adds intelligibility to the vocoded sound, however it works just as well (even better, some might say) with non-vocal sources, particularly rhythmic sounds. Unusually this VUD allows for the internal noise generator to be overridden by an external source, a vocoder with three audio inputs , is this unique? I don't know but it does open even more creative sound shaping avenues. Of course getting the PCP330 to produce some decent sounds depends a lot on the source material and you can't expect to get those more unusual and whacky sounds straight away, you need to spend some time experimenting.

During this review I used almost anything that had an output signal to drive the various vocoder inputs, here are some examples: Digital synth, analogue synth, Bassline, drum machine, drum pads, fuzz guitar, samples and sample loops, effect unit, radio, TV and PC sound card. The fun part is trying out the various combinations of these, which often result in some unexpected results and happy accidents. An interesting input combination I came up with was feeding a Bassline through the Modulator (analysis) input, an evolving synth pad through the Carrier input (or Synthese input, as it says on the rear panel) and a hi-hat pattern through the Unvoiced input. By adjusting the Sibilance level (which behaves a bit like a frequency dependent noise gate) it was possible to go from a smoothly changing, vocoded bubbly bass sound, through to a chopped up, hard edged rhythm. And by adjusting any of the eleven filter levels it was possible to reduce or accentuate the bass, middle or top end ranges of the overall sound. Although the PCP330 includes a compressor to reduce the likelihood of overloading the inputs I still found it quite easy to push the vocoder into distortion. But because this is an analogue unit this isn't an entirely unpleasant experience and I can imagine some people using this feature to produce some suitably grungy lo-fi vocoder sounds.

As I mentioned elsewhere the PCP330 can also function as a filter-bank. We're not talking graphic or parametric just 11 fixed, band-pass filters (from 50Hz to 12kHz), with a level control for each. The unit works well enough as a basic filter but because the bands are fixed and there are no width or Q controls it's quite limited and I doubt if this feature will get much use. The manual contains some useful instructions on how to configure the vocoder to produce other non vocoder like effects. These include various types of pseudo filter sweeps, 'Rhythmatizing' static sounds (as I described above) and frequency dependent distortion. This last effect works by feeding the same signal into both analysis and synthisis inputs and allows you to tune the distortion across different frequency bands by adjusting the individual filter levels. (for more vocoder uses see box below)

A few years ago I used to have a Roland SVC350 vocoder, which was also an 11-band unit and I currently use the Korg Wavestation A/D vocoder, which only has about 6 or 7 bands. And while the Roland sounded very warm and the Korg sounds clean, neither have the strong, vibrant tones of the PCP330. Occasionally it can sound a little too resonant in the mid section but with careful tuning this can be eliminated and when processing drum loops and bass lines it can pack quite a punch at the bottom end. But beware of introducing the Sibilance (unvoiced) effect too quickly as it can change the sound, quite alarmingly, from a gentle chorus like sound, to a loud sandpaper scratch. Output mixing is also comprehensive with level controls for Carrier (mic/line), Modulator (VCO), Vocoder and Filter-bank, which allows for some complex layering of timbres.

The adverts Turnkey are running ask the question "Why doesn't anyone make a vocoder anymore", well they do actually, as I'm pretty sure EMS still produce a professional vocoder (with a pro price I imagine), while at the budget end of the market the new Zoom 1202 and 1204 multi-effects units apparently contain good vocoder algorithms and at only £99 and £199 each too. So where does this leave the FAT PCP330 Procoder at £299? Well you could argue that it 's just a one trick horse, particularly without MIDI, CV control or a foot switch socket? Also, having no marked graduations around the knobs makes it very difficult to make a note of any particularly good settings you may come across. But as I've said previously the vocoded sound is particularly strong and with more than enough controls to shape and tweak the sound. Also it does make a change to see a manufacturer coming up with something a little different, instead of cloning the same old bass lines, drum machines and filters. But unfortunately I have to say that I think the £299 price is on the high side and £249 would be a lot more realistic, particularly when compared to the Zoom units. Couple this with my reservations about the build quality and I'm afraid I can't recommend the PCP330 as wholeheartedly as I would have liked to. FAT need to sort out their quality control with regards to the case and PSU, because it doesn't matter how good the engine is if the bodywork is crap. Taken as a whole it looks like too many corners have been cut and it just doesn't come across as good value for money. All I can say is try one in the flesh before you part with your cash.


Price: £299 including VAT.

Turnkey Group
114-116 Charing Cross Road
London WC2H ODT.
T: 0171379 5148
F: 0171379 0093

A versatile, great sounding machine, capable of producing some extraordinary and unusual effects. Only let down by the presentation and price. Try before you buy.

Versatile and easy to use.
Capable of producing some great sounds, with the right source material.
Good audio quality, even the distortion sounds OK.
A separate control for everything.
XLR socket for mic input.
Built-in oscillator.
Three independent audio inputs.

No on/off switch.
No foot-switch socket.
Case has poor build quality.
Cheap and trashy appearance.
No external CV input for oscillator.
Average value for money.

Talking instruments
Pitch shifting vocals
Changing voice timbre
Disguising voices
Telephone or lo-fi voices
Stephen Hawking impersonations
Ethereal chorus sounds
'Rhythmatizing' static sounds
Robot or Dalek voices
Ring Modulator type effects
Frequency dependent noise gating
Frequency dependent distortion
Phaser type effects
Fixed filter-bank



The PCP330 sounds great, there's no denying it but as far as build quality goes it's a Dodo. As soon as I unpacked it I knew something wasn't right. For a start the top and bottom plates of the case aren't fixed to the frame but sit in grooves and rattle about and the overall impression is one of a Maplin self-assembly kit, with sharp, unfinished burring on the edges of the aluminium front panel. Place this unit anywhere near a loud monitor or bass bin and the loose plates rattle like mad. Also, I know FAT are trying to recreate that 70's look with suitably tacky shocking pink and blocky lettering but if viewed from the wrong angle or in anything other than bright light the lettering is almost illegible. Finally this brings me to that recurring (and boring) problem, wall wart power supplies. OK, so I have given up my King Canute like attempt to have any sort of influence whatsoever over whether manufacturers use internal (yes please!) or external power supplies (no thanks!). But the unit supplied with the PCP330 reconfirmed my worst fears. For a start it's a horrible AC/AC type not a standard AC/DC unit but more worryingly, not only was the AC adapter socket badly misaligned on the rear of the vocoder case but the plug just kept falling out of the socket, literally fell out. The only way to hold it in place was by strapping a length of gaffa tape across the rear of the unit and I certainly wouldn't consider gigging it in this condition. The problem with the PSU is hopefully only restricted to the review model but I'm not so sure about the case. You just don't get a feeling of quality and professionalism, which is ironic for a unit called a Procoder. FAT need to seriously sort out their quality control.

Copyright © 1997 Chris Carter / SOS Publications.