Quilcom Q-50 | Free VST Synth Instrument

Quilcom Q-50 | Free VST Synth Instrument by Rex Basterfield

The Quilcom Q-50 is a free VST synthesiser instrument inspired by the Roland D-50. It’s not an emulation and the presets and embedded wave files are not a copy of the originals. However the architecture is very similar.

The original D-50 replaced the Yamaha DX7 in terms of popularity back in 1987. It used a method now referred to as sample and synthesis and was easier for users to understand, and use, than FM synthesis and yet was still all completely digital.

The principle of the synth was to use tried and tested familiar analogue-type metaphors and routing, but combine these with acoustic and other samples for the attack phase only. Since memory was very expensive back then it simply wasn’t economical to create a full blown sampler so Roland supplied a built-in ROM with a ‘whopping’ 8MB capacity pre-loaded with 100 8 bit attack-phase and other PCM samples.

The basic architecture for the D-50 and Q-50 is as follows: A patch (preset) is made from 2 Tones called Upper and Lower. Each of the 2 Tones is made up of 2 Partials. The 2 Partials can each be either a Wave or a Synth. This means you can be using any 4 from 8 generators available.

Each of the 2 Tones has a static filter, a chorus/delay and a Ring Modulator. The final outputs from the 2 Tones are fed into a reverb.

Each Wave Partial has a choice of sample used, pitched or static, single shot or looped and can be tuned in pitched mode. The wave is then fed into an ADSR envelope stage.

Each Synth Partial comprises a tuner, waveform selector followed by a filter with its own ADSR and a separate amplitude ADSR.

Both types of Partial have, in addition, LFOs available for various functions and a Pitch envelope generator.

Of course there are differences in the Q-50:

  • Each Partial has 4 LFOs rather than 3. This means each one has a specific assignment.
  • Stereo is possible since the Upper Tone is routed left and the Lower right. Width can be adjusted.
  • The samples are 16 bit 44.1Khz so sound much cleaner
  • You can load any single User sample instead of using the ROM; its path is stored in your preset.
  • There are more waveforms available for the Synth Partials and the LFOs
  • There are more filter options available for the Synth Partials
  • The Tone mixers can have levels set for Partials 1 and 2 AND a Ring Modulator; you don’t have to choose either-or.
  • The parametric EQ is far more advanced than the D-50’s


The first 50 presets all use at least one of the samples. The Q-50 should really be thought of firstly as a synthesizer but which can also be enhanced with samples.


Price: Free

Info & Download >> Flowstoners / Quilcom Q-50

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