Erica Synths - Black Varishape VCO 2


The Black Varishape VCO2 is the twin of the VCO1, but it lacks the X-Mod FM which has been replaced by a detune control. For that reason it's suited as the secondary or tertiary oscillator in a Erica Synths system. Besides this it is also a neat VCO from the Russian Polivoks synth, featuring a transistor based suboscillator besides a bi-polar waveform mixer for creating new waveforms.



Analog voltage controlled oscillator with stable tracking over 7 octaves which is pretty much for an analog VCO.
The Varishape VCO2's tuning controls consist of a seven-position rotary switch, a frequency control and a dedicated detune control for extreme fine tuning by just a few semitones. What's the idea behind that? Well, in vintage compact synthesizers often only the first VCO had a wide-range tune control and the other VCOs featured a detune control only. So the the intention behind the Varishape VCO2 is: use it as a secondary or side oscillator, e.g. in a Polivoks Clone made entirely of Erica's Black module series!

The Black Varishape VCO has no individual waveform outputs but a mix output instead. For each waveform (triangle, sawtooth and pulse) a bipolar control is available which will add the wave to the mix, either with correct phase or phase inverted; this way the waves interact with each other and new waves can be created. The mixer turns into a wave shaper!

The pulse width can be adjusted manually or modulated via the scalable CV input. Same like on the original Polivoks VCO the triangle wave has a spike and is relatively rich in harmonics. The pulse width modualtion will also affect the triangle and thus it's sound which is similar to the original oscillator's behaviour.
In addition to the three waves a transistor based sub oscillator with a specific sound can be found which is added to the mix with correct phase.

The laggy transition when switching octaves is implemented on purpose. On one hand the glide is a nice effect and on the other this will omit audible clicks.


The oscillator is entirely analog and has to warm up for 15-20 minutes for a perfect and stable tuning.

Ericas Black Series is a line of high-quality modules forming one entire system. They are buit with quality components; all inputs and outputs are protected against overvoltage; the module is protected against reversed polarity. All important parameters have large controls.
Design and usability were put before economic width.


1V/oct input, exponential FM input, PWM input, oscillator output


3U Eurorack module, 18HP wide, 30mm deep
current draw: 50mA @ +12V and 45mA @ -12V

0.25 kg
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