I recently heard that the FB-383 is EXACTLY the same unit as the MAM MB-33, with a new packaging, and it was designed only for UK customers (limited edition of 100 units).
Quoting their Web site :
"Superb first product from new manufacturer Freeform Analog Technologies. The only authentic sounding TB303 clone, with MIDI. 1U rack with 1 knob per function, all the sound controls of the 303 are duplicated, Cutoff, Resonance, Envelope Mod, Accent, Tune and Decay. Waveform is continuously variable from square wave to sawtooth, and an auto tune button is included to retune the oscillator. Filter cutoff CV controllable (convertor box available only £69 if bought with FB383) The ultimate analog bass machine - this incredible price means these will fly out of the door! Turnkey Exclusive."
Here's a review from Geraint Howell, from AH :
Ok, a little late, but finally, as promised, an FB383 review for the archives. Apologies for any errors. -------------------------------------------------------------- The FAT FB383 is a low cost TB303 emulator, available from Turnkey, in London, UK. AFAIK, it is identical to the MAM MB-33, and is just marketed in the UK under a different name. Ok, so what do you get for your money? Its an analogue mono synth with one osc, housed in a 1U rack. It has one Midi In port around the back (no Thru, or Out), but it only responds to Note On/Off messages - you can't control the filter via Midi cc's, so all your mixes have to be done on the fly, unless you're multi-tracking. There's no provision for CV/Gate. You get knobs for: VCO Tune - just fine tune for pitch, plus or minus a semitone - you also get an auto-tune button, which tunes the osc to concert pitch. This function executes as soon as you fire up the unit, making it unavailable for around 30 seconds. VCO Wave - the osc can be set to saw or square, or rather a balance between the two. This is a nice touch which allows you to get some nice variations to the sound. VCF Cutoff - Self explanatory. VCF Resonance - Self explanatory. VCF Env Mod - This knob determines how much effect the accent & decay knobs have on the sound. VCA/VCF Accent - If the unit receives a note with a velocity of over 100 (I think), then that note is 'accented.' In practice, this means that the VCF Cutoff is wide open for the duration of that note. This is the only touch sensitivity that the unit responds to. Envelope Decay - Only the decay of the ADSR is variable, as on the TB303. You can get a *lot* of variation by altering this knob. The rest of the ADSR is set to be as similar to the TB303 as possible. Master Volume - Self explanatory. Other Info. - If you play in a staccato fashion, then the ADSR is reset every time you play a not. If you play legato, however, then (i) the ADSR is not reset, but rather the next note continues where the previous left off, and (ii) the glide kicks in. You get an external input to the filter. I haven't really experimented with this yet, but I already have a winge about it. By plugging a jack into the external input, the osc is automatically disabled. This is a drag for me, as the input is right around the back of the unit - not easy to get to if its in a rack. I'd like to just set it up on a send/return loop from my desk, but this is not feasible if you are switching between the osc and the external input - you have to keep plugging and unplugging the damn lead. :( Also of note is the build. If a very small 1U box, about the size of a small FX unit, like the Zoom 1201. The build does not strike me as being overally rebust, the metal the box is built out of seems quite soft. I've had mine about 4 weeks, and one of the ears is slightly bent. That said, once its racked up is should be safe enough. You need an external PSU (provided) for the unit.. To summarise, then, this is a cheap little unit with a nice big acidic sound. The Midi spec could be more impressive and there are other units on the market that do a similar job, and offer extras like Midi control of cutoff/resonance, and CV/Gate Ins and Outs, but most are more expensive. I got mine for 130UKP, and at that price I'm not complaining. :)
FB-383's price is friendly £199 !!