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Another Roland TB303 clone from German manufacturers Music and More (MAM). One of the many TB303 clones manufactured in the last thirty years, the MAM FB383 was also sold under the FAT brand name & distributed by the Turnkey Shop in London’s Charing Cross

The MB33 is virtually identical to the Freebass 383 but has a front panel like the Analog Filterbank 8. The MB33 has been reborn in desktop form as the MB33 Retro

Like the original Roland TB303, the MB33 is 100% analogue and sounds like it. It’s super-simple with a set of controls that are always live. There are no menus to dive into, no presets, no complex routing – just a simple synth with a super-expressive filter

The back panel has a VCF input which bypasses the oscillators and allows external audio to be fed to the filter. Midi channel selection is also on the back panel via DIP switches so it’s best to set it & leave it alone

“The FB 383 offers all the same basic sounds and controls as the original TB-303 in a 1-unit rack module. It has just 8 basic knobs for the same basic 303-like control: tune, filter cutoff, resonance, envmod, accent and decay. Unlike the 303 however, the oscillator can be varied from sawtooth to square from a knob on the front! Also featured is an external audio input to the filter for processing other elements”

“The Freebass is limited but sounds good to me, real VCO and an authentic 303 filter – it feels and sounds like a real analogue synth”

“I think for price and availability the Freebass FB383 seems to fit the bill for me and judging from the sound-bites that I have heard it seems to offer a more than usable sound”

“I have one of these for about 2 years now and i still use it. it sounds good as 303 clone but i use it for normal bass sounds too. nice percussive bass psy sounds are possible with it”

“I have to say that this is one hell of a synth for a cheap price. The 383 can make low, percussive and chirpy bass”

“What can i say! amazing, just gotta hit it with the right type of pattern and you’ve got a TB right there”

In great used condition with minimal rack rash. External power supply included. Tested & working 100%. Photos show the item for sale

Rackmount TB303 clone in the darker MAM / FAT style in a super-shallow 1U box with external power supply. Connections are unbalanced on jack sockets. VCF control input is on the back panel

The MB33 is monophonic and has one oscillator with mixable sawtooth and square waveforms

Filter is a 24 dB/oct lowpass with cutoff-frequency, resonance & ENV-modulation controls. The VCA has an envelope and accent control for velocities > 120

Standard 1U rackmount device, external power supply

Matrixsynth page

Deepsonic MAM page

Gearslutz thread on TB303 clones

Matrixsynth page

Encyclotronic page

Sonicstate review

Acidvoice clone demo page

Vintagesynth review

Circuitbenders description

Youtube demos


Very good used condition with minimal rack rash or case marks. Supplied with external power supply. Tested & working 100%. Photos show the item for sale