Electronic Musician reviews a feature-packed analog synthesizer module, the Black Coffee from Analogue Solutions. This monosynth includes a Moog-style 24 dB lowpass filter and a gritty sounding oscillator.
By Mike Peake,

Analogue Solutions' Black Coffee is an analog synth module that maintains much of the sonic character of larger analog synths but in a portable package and at a reasonable cost. It is housed in a rectangular, black plastic case that is slightly larger than a stack of paperbacks. But don't let its size fool you — the Black Coffee offers an impressive amount of functionality within the space of most single-function analog synths.


The Black Coffee was designed in the tradition of early monophonic synths, but with the modern convenience of a built-in MIDI-to-CV converter. The module is a complete synth in itself, combining an oscillator with sawtooth and square waveforms, a suboctave generator, an LFO with sawtooth and square waveforms, an AR (attack and release) — style envelope generator (EG) with switchable sustain, a noise generator, a lowpass filter, a ring modulator, and a VCA.

On the front panel are eight ⅛-inch jacks for patching to and from external sources. The jacks include CV inputs (pitch, pulse-width modulation, oscillator sync, filter cutoff, and trigger), an audio input, and two audio outputs, including an LFO output. The front panel also includes ten knobs and six switches. Six of the knobs act as 2-position (push/pull) switches.

The rear panel houses an additional audio input and output, MIDI In and Thru ports, a MIDI-channel selector, a manual-trigger button, and a CV pedal input and associated level control (see Fig. 1). Four large rubber feet help keep the module from sliding around as you work.

If you want to mount it in a Euro subrack, the Black Coffee can be purchased without the case, power supply, or MIDI ports ($339). In a modular configuration, it is compatible with other modules from Analogue Solutions as well as those from Analogue Systems and Doepfer.


A front-panel Tune control adjusts the Black Coffee's slightly gritty oscillator over a two-octave range. MIDI and external CV signals extend the pitch range to six octaves.

The Mix control is used to select the oscillator waveform: turn the control fully clockwise, then pull the knob to get a sawtooth wave or push it for a square wave.

A toggle switch next to the Mix knob selects whether noise/suboctave or ring modulator/external audio is mixed in with the oscillator. The in/out position of the knob determines which signal is heard: with the Mix pot pushed in and set fully counterclockwise, setting the switch to Noise/Sub will give you the noise source. Pull the Mix pot out and you will hear the suboctave oscillator. Set the toggle switch to the Ring/External position and turn the Mix pot counterclockwise to get the ring modulated signal when the pot is pushed in, or the external audio signal when the pot is pulled out.

The Black Coffee oscillator doesn't track perfectly throughout its entire range. For melodic material, it's most useful within a four-octave range. However, it can be optimized for a particular range by adjusting the internal Scale and Tune controls. The tracking artifacts do, however, add somewhat to the Black Coffee's vintage sound.

The warm, Moog-style 24 dB lowpass filter can be set into self-oscillation. Pulling out the Cut-Off control adds audio-rate frequency modulation from the oscillator. The result is a nice fattening and slight brightening of the sound when filter resonance is absent, and an edgy, aggressive sound when resonance is added.

However, when the Mix knob is set to either extreme, you can hear bleed-through when the filter-frequency control is set near minimum. The bleed-through can be reduced by keeping the Mix control between the 9 o'clock and 3 o'clock positions when using the sawtooth wave. But when the square wave and noise generator are selected, you can hear noise bleeding into the filter, even when the Mix control is set fully clockwise.

Although the Black Coffee has a Moog-style filter, it self-oscillates at a much lower frequency than the original Moog-modular filter. But as with other filters of this design, bass response decreases as you increase resonance. This allows you to create mid-bass kick drums as well as snappy percussive sounds.


The Volume control is also a push/pull knob. When pushed in, the EG controls the module's VCA. When the Volume pot is pulled out, you can use another switch to select between two modes of operation. In Drone mode, an external signal passes through the module regardless of a key trigger. In Gate mode, the volume turns on sharply with each note, remains at full volume as long as a note is held, and then falls to silence immediately after the note is released. Gate mode allows you to use the EG to sweep the filter and oscillator at different rates.

The Black Coffee's EG has a fast, snappy response and a maximum release time of 26 seconds. Unfortunately, the attack time doesn't go beyond 3 seconds. The VCA exhibits an audible tick in response to minimum envelope times. It's also a tad noisy, but well within a musically acceptable range. In addition, loud, high-frequency signals fed into the external audio input are audible even when the module's volume is turned off.

The LFO comes with controls for frequency and depth, and you can select either a triangle or square waveform. To modulate the oscillator's pitch with the LFO, pull out the Tune control and choose one of the two predetermined speeds. To modulate the filter, pull out the EG Mod control. An LED displays the LFO rate.

The EG or LFO can modulate the pulse width of the oscillator's square wave by a predetermined amount. The LFO amount is musically satisfying, but the EG amount is a bit too subtle for my tastes.


The Black Coffee synth includes MIDI functionality, albeit at a bare-bones level. Rear-panel DIP switches select the MIDI channel, and all MIDI-to-CV connections are internally set and cannot be defeated. For example, Velocity and Pitch Bend control the filter cutoff by a fixed amount, and a Note On sends a gate signal to the EG.

However, MIDI control gives you access to the Black Coffee's otherwise hidden slew generator: when two notes are played simultaneously, a small amount of portamento is automatically introduced between them, an effect reminiscent of the Roland TB-303. The MIDI interface also lacks normal pitch-bending capabilities, signifying to me that it is intended for pattern-based, note-entry sequencing rather than, say, keyboard soloing.

I also connected the Black Coffee to external MIDI-to-CV converters with a limited amount of success — one of my two converters would not trigger the EG. I tried the manual's suggested work-around of patching the LFO square wave output to the EG trigger input. In both instances, the trigger LED lit, but the EG didn't fire. The Manual Trigger button on the rear of the unit functioned consistently.


The Black Coffee packs a surprising amount of features into a small box. It excels at slightly menacing Moog-style bass sounds, especially when the suboctave oscillator, pulse-width modulation, and filter frequency modulation are combined.

As a simple module — without the case and MIDI features — the Black Coffee is a bargain and would be a good place to begin building a modular synthesizer. But as a tabletop unit, the Black Coffee is a nice alternative to buying a vintage monosynth and adding a MIDI retrofit. It has a desirable character all its own.

Mike Peakehas been a modular-synthesizer enthusiast since 1978.


Analogue Solutions
Black Coffee
analog synth module


PROS: Multiple features in a small space. Portable. Built-in MIDI-to-CV converter. Externally patchable. Audio input.

CONS: Unable to defeat MIDI. Audible signal bleed-through. Incompatible with some MIDI-to-CV converters. Plastic case seems fragile. Dark blue graphics are difficult to read in dim lighting.

Analogue Solutions/Sweet Noise (distributor)
tel. (818) 980-6983

Black Coffee Specifications

Sound Engineanalog subtractive synthesisPolyphony1 note (monophonic)Audio Inputs(1) ⅛" on front panel; (1) ¼" on rear panelAudio Outputs(1) ⅛" main and (1) ⅛" LFO, both on front panel; (1) ¼" main on rear panelPatch Cord Connections (CV and audio)(8) ⅛" minijacks on front panel; (3) ¼" and (1) ⅛" on rear panelSound Sources(1) VCO; (1) suboscillator; (1) LFO; (1) noise generatorFilter(1) resonant lowpass; 24 dB/octaveEffects Processor(1) ring modulatorAmplifier(1) VCAMIDI-to-CV ConverterMIDI In and Thru; pitch, modulation, gate, accent, and legatoPower15VAC, 500 mA wall wartDimensions4.00" (W) × 5.25" (H) × 8.00" (D)Weight2.2 lb.

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