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Freeform Analogue Technologies Freebass FB383

Analogue Monosynth By Paul Nagle
Published March 1997

People keep on making 'em, people keep on buying 'em. Is there no end to the appetite for TB303 clones? Paul Nagle checks out one of the cheapest yet, and concludes that FAT is good for you after all...

I have a strange, recurring dream which is set in a plush office somewhere in Japan. In it, an exasperated Roland salesperson declares: "You're the tenth person I've told today: there just isn't any demand for it!" and then slams down the phone. The enquiry concerns the legendary TB303, Roland's little silver plastic Bassline. Of course, the decision not to start making the 303 again is based on sound business strategy and years of experience. As to whether it's right or not — let's just say that numerous other companies depend on it, not least Freeform Analogue Technologies, who believe that there's room for yet another 303 clone in an already crowded market. So, without further ado, let me introduce the FB383 Analog Synthesizer, or Freebass. OK — it's not free, exactly, but, being priced at just under the £200 mark, it must rate a listen if Basslines are your thing.

The Freebass is the smallest rack‑mounted synth I have ever come across, being just 2.5 inches deep and occupying a single rack space. With its silver and orange front panel, it definitely has a retro look — it would not be out of place alongside disco oil lamps and flared trousers! The knobs are all reassuringly smooth and chunky, with functions chosen to mimic the TB303.

The rear of the unit features a MIDI In socket (no Thru), the inevitable external power supply connector, standard quarter‑inch jacks for the audio out and the external input to the filter, and four DIP switches which are used to set the MIDI channel. One flick with a tiny screwdriver to select the channel I wanted, and I was ready to go.

Open That Box

First impressions are important. Before getting deeper into the Freebass, I was struck by the fact that if you play legato, an irritating preset portamento is introduced to the sound. Of course, I never had the opportunity to play my own TB303s via a keyboard (all programming being done in step time), so I switched on my Korg Prophecy and let the Prophecy's arpeggiator run frantically for a while as I twiddled knobs on the Freebass. Played in this manner, the Freebass took on an instant air of authenticity.

It's a strange business reviewing a synth whose sole purpose in life is to reproduce the characteristics — even the limitations — of another. There was no point in looking for second oscillator or, indeed, any feature that was not present on the original TB303. Instead, I simply assaulted it with as many acid/techno patterns as I could and conjured up lots of different sounds. There were more of these than I expected, but all very firmly in Bassline territory.

Although a MIDI implementation chart isn't included in the four‑page manual, the FreeBass's spec is pretty easy to work out. It responds to Note On and Off information, but not much else, and if you want to manipulate the controls, this must be done live — exactly as you would on a real 303. On the whole, I prefer the approach of, for example, the Deep Bass Nine, which allows access to the filter or portamento settings via MIDI. It's not compulsory, after all; die‑hard purists still have the option to do things the old way.

The synth has a playable range of four octaves which, given its intended use, is fine. With no octave selector or key shift, the notes you play are the ones you get.

Wiggle Them Knobs

Since the Freebass is so uncomplicated, we can afford the luxury of looking at each knob in turn (very much as my wife does when attending a musical soirée with those lively young fellows the Chippendales). Two LEDs indicate the presence of power and MIDI information respectively. On power up, the MIDI light stays on until the auto‑tune function has finished. This facility can be activated at any time from a front‑panel switch, although it disables the synth for some 30‑40 seconds while it does its calibrating. For this reason, perhaps it should have been positioned at the far left of the panel to prevent accidental and potentially embarassing silences!

Now for those knobs: the fine‑tune knob allows transposition by a semitone up or down, which should be enough to tune to most modern instruments. It can also function as a crude pitch‑bend function if you wish. The waveform knob is described in the manual thus: "The FB383 generates both square and sawtooth waveforms. This control is used to control the balance of these two waveforms." I must say I can't agree completely. It actually does a little more than that — or I've got something strange living in my ear. In fact this knob fades through several different timbres, from a fat‑sounding square wave, to a more hollow and pure square wave, then a mixture of square and sawtooth, a high, bright sawtooth and, finally, a deeper, fuller sawtooth. A setting at each extreme will give the closest match to the TB303's throbbing oscillator, but the small variations between are welcome and increase the versatility of the Freebass. To check out the differing characteristics, crank the resonance up to full and sweep the waveform knob all the way round.

The cutoff and resonance controls are extremely smooth, matching the range and operation of the 303. Resonance increases the electronic (or squelchy, if you want the technical term) nature of the sound, emphasising the frequencies around the cutoff. True to form, it doesn't significantly affect the bass components in the sound, unlike the resonant filters on many synths.

Accent comes into play with notes having a velocity of 120 or more, and adds a mixture of increased volume, cutoff and resonance settings, combined with a faster decay. Other than this, the synth doesn't respond to velocity, which is another reason why it sounds so similar to a TB303 right out of the box. Decay sets how quickly the filter is closed and is used in conjunction with Envelope Mod to produce sweeps and punchy attacks. Increasing the envelope modulation amount and shortening the decay time gives the characteristic filter blip that pervades most acid tracks.

A final knob is dedicated to overall volume control. I never found the need to change this from maximum, because I did most of my processing via the mixing desk. The Freebass has a strong, raw sound which responded particularly well to a selection of distortion, delay and other effects.

And that's really all there is to think about! A preset VCA envelope ensures that you'll never stray into unknown territory, and the sparse controls are all that's needed to extract all those beloved TB303 sounds with remarkable accuracy. Even though I haven't played every other clone on the market, this one is certainly close enough for most people who want the sound of a 303.


There's something reassuringly organic about a synthesizer with knobs whose positions aren't translated into absolute values on some form of display. Suddenly there seem to be more possibilities, endless combinations, and an almost infinite scope for subtle variation. The Freebass delivers TB303 sounds accurately enough for all but the most dedicated follower of fashion. The quality of the controls is superior to the original instrument's, and the style is a refreshing change from the drab black boxes that inhabit racks everywhere. 'Garish' is another (less kind) description. If Roland ever do start to make the 303 again, it is more likely to be in the form of a computer‑modelled version. Everyone will discuss how closely it copies the real thing, totally forgetting to question just how far this programming feat has taken us! The FB383, though, is a purely analogue machine with all the natural warmth and control you'd expect. And if you're not using the Freebass for bass lines, its external input means that you can process other instruments with its distinctive filter — something I'd probably do a lot.

Reservations? Well, I wasn't exactly blown away by the MIDI spec and I worry that if the TB303 bubble ever bursts there will be a whole load of synths that no longer have a reason for existence. Despite being a single‑oscillator monosynth, the Freebass manages to be both fat and a joy to tweak. After being initially sceptical, I found myself pretty convinced, and concluded that if I ever wanted another 303, this would do very nicely.

Fat Filter

I'd probably have been quite impressed, given the price tag, if the Freebass had simply offered the features I've covered in the main body of this review, but there's an extra ingredient included to broaden the Freebass's appeal somewhat — an external input to the filter.

Connecting a succession of synths and drum machines to the filter input gave results ranging from good to superb. I was most impressed by the improvement to my JD800: for those of you who are interested, the JD has a digital filter which, although reasonable, has a rather nasty resonance which requires careful use. The filter on the Freebass added a warmth to my JD that alone almost justifies the synth's price tag. Pretty much any digital synth will benefit from a filter of this type, and even drum machines and samplers can take on a new lease of life when you give them a good resonant twang. I soon noticed that only a low level was needed or distortion crept in — not that this always sounded bad, especially with drums. As with most external filter units, you need to trigger the FB383's envelope section before you will hear any sound. This is independent of the triggering of your sound source and can be used creatively — as in pre‑MIDI days before a note's pitch and gate signal became irrevocably bonded together. When an external signal is connected, the internal synth is disabled — meaning that you can't leave it plumbed into a patchbay, for example. Also, if you had the Freebass racked up, it might become rather inconvenient to keep stretching around to the back of the unit to connect and disconnect synths from the filter input.


  • An affordable TB303 in a rack.
  • External input to the filter.


  • MIDI implementation rather basic.


With the Freebass in your arsenal, you have the same range of sounds as from the original Bassline but with an analogue filter unit thrown in. The MIDI spec is spartan, but remember that the original TB303 didn't have MIDI at all, so it could be argued that this is both a purist approach and a means of keeping down the price.