Cwejman SM-1 synth module, grey

The Cwejman SM1 is a semi modular synthesizer voice that can be played instantly via CV/ Gate.

The module contains two oscillators, a multimode filter, VCA and two ADSR loop envelopes and LFOs. All sections can also be used individually thanks to many patch points.

The master section offers an octave switch with a total of 7 positions. Tracking can be activated separately for each oscillator and for the LFO1 via small switches. In addition, voltage can be smoothed thanks to the glide control. The tracking for the filter cutoff frequency can be variably adjusted thanks to a potentiometer.  
The two LFOs each offer seven different waveforms, including a random voltage. The speed is adjusted manually with rotary knobs or via control voltage and indicated by LEDs.

The two oscillators have an identical layout, with individual controls for volume and FM. The Sync switch allows the second VCO to synchronize with the first. The pitch can be adjusted with potentiometers for coarse and fine tuning. Six waveforms are available, including pulse width and PMW modulation. VCO1 also provides noise, and VCO2 can be used as a ring modulator when the waveform selector is set to a specific position, either with the first oscillator or with the external signal. Each VCO provides two FM inputs with dedicated attenuators, and the FM1 modulation can be positive or negative thanks to the switch.  

The Multimode Filter is a slimmed down version of the MMF-1S with seven reversible filter types and two selectable slopes for most of them. Combined, this results in eleven different filters:

• Low pass with -12 or -24 dB per octave
• High pass with -12 or -24 dB per octave
• Bandpass with -6 or -12 dB per octave
• three dual bandpasses: two peaks, upper peak, lower peak
• single notch (in -12 dB position), dual notch (in -24 dB position)

The Res/Osc switch determines whether the resonance begins to oscillate at maximum or not, allowing for a wide range of sounds.
The show stopper is that with the dual filters the distance between the two resonance peaks can be adjusted via the SPACING parameter, which is great for creating vocal sounds! A total of three knobs are available to influence the filter cutoff frequency. Thanks to separate controls, it can be controlled from envelope 1 or 2, either in the positive or negative range. Additionally it can be controlled by VCO1, LFO1, LFO2 or an external control voltage. Thus, very complex modulation can be realized in no time at all.

In addition, the filter offers a saturation stage with two selectable types, which distorts the signal nonlinearly.

There are two identical envelope generators available which can be triggered by a normalized socket from a common signal. Two LEDs indicate the course of each envelope. All parameters (Attack, Decay, Sustain and Release) are voltage controllable. Both envelopes can be switched to Loop mode using individual switches. In addition, the characteristics of the second envelope can be switched from linear to exponential.

Master section inputs: 1v/oct.(Tune), LFO1 rate CV, LFO2 rate CV, Sync
Filter section inputs: Ext. Audio, ext. Cutoff CV, Resonance CV, Spacing CV
Inputs per oscillator: FM1, FM2, PWM, Sync
Inputs per envelope: Gate, Attack CV, Decay CV, Sustain CV, Release CV
VCA section input: Velocity
Outputs: Filter, Voice, LFO1, LFO2, ADSR1, ADSR2

3U Eurorack module, 56 HP wide, 29mm in depth
Power consumption: 150 mA at +12 V and 120 mA at -12 V