Chernobyletta Eurorack Module - Noise and Drone Oscillator Synth with CV Offset, Distortion, Power Starve and Touch Controls. Fully built. Black & Silver version.

CHERNOBYLETTA
Distortion/drone/noise Eurorack module by Isn’tses

The CHERNOBYLETTA is a distortion/drone/noise Eurorack module developed from the 'Chernobylizer' standalone noise synth. It's 20hp wide and requires a standard eurorack power supply.

The main signal is created by 6 oscillators which are controlled by knobs, CV, power starve and a unique power drain function, and modulated by touchpads. The chip which creates these 6 squarewaves is powered by the CV input, giving an unusual kind of voltage control over the noise which gets very chaotic at lower voltages. The Gain and Offset knobs give you the flexibility to use bipolar signals, (eg LFOs or even audio) unipolar signals (eg ADSR, sequencers etc) or any other eurorack signal, and the module is also fully playable without any CV input. 

Inputs + Outputs
CV input - Connect a control voltage (e.g. LFO, ADSR, sequencer or audio) here to control the overall pitch of the oscillators. Rather than a conventional VCO circuit, the CV directly powers the oscillator chip so this is not voltage-per-octave, or even HZ/Volt, but works in it’s own warped and unorthodox way while being very playable and having a wide range.

CV output - This is an optional output from the CV scale/offset controls, and can be used to send the the modified CV signal to other modules.

Distortion input - This overrides the oscillator signal so that you can run external signals through the distortion instead. When something is plugged in here, you will hear that signal out of the main output instead of the 6 oscillators. However you can still get a non-distorted version of the 6x oscillators signal out of the secondary output jack.

Main (distorted) output - (4th jack from the left) This is usually used as the main audio output. The overall loudness and distortion level is controlled by the Distort knob.

Secondary (non-distorted) output - (5th jack from the left) This is a clean signal from the oscillators without any distortion. It’s usually quieter than the main output and has a different sonic character. Its overall volume may drop when the starve controls are used. This signal is mainly intended be processed though other fx/gain/distortion/filter modules for different sounds. It can also be used to make a feedback loop when patched back into the CV input of the Chernobyletta.

Controls:

CV Gain knob - Controls the CV input level, from zero all the way up to fuzz/distortion levels which can square off the CV waveform if you want. Note that if you don’t have a CV input connected this knob does nothing.

CV Offset knob - Adds a bipolar offset to the CV signal so you can tweak it positive (clockwise) or negative (anticlockwise). You can take this to extremes, clipping the CV into complete positive or negative DC offset if you desire. Without a CV input jack connected, the CV Offset knob controls the overall pitch of the oscillators directly and manually.

Distort knob - Controls the amount of fuzz/distortion/gain on the main output. The distortion circuit is very high gain and can go very loud. It uses LEDs as clipping diodes, these shine through the front panel so you can see as well as hear the noise. 

Oscillator 1, 2, 3, 4, 5, 6 knobs - These 6 knobs individually tune the pitch of the 6 starved oscillators, which are then mixed together and sent to the outputs. They have a wide range so you can go from near-ultrasonic high pitches right down to low rumbles, crunches and clicks below the audio spectrum. 

Drain switch - Switching this upwards injects a fixed voltage into a bank of large capacitors. When the drain knob is turned anticlockwise this takes over the CV signal. Subsequently switching it off again cuts that voltage source and you get the classic Chernobylizer power drain effect.

Drain knob - When turned anticlockwise, this reroutes the CV through a bank of large capacitors which can also be charged by the drain switch, causing weird smoothing of the signal and a gradual draining effect. When turned all the way clockwise the drain effect is turned off and the drain switch position doesn’t effect the sound.

Starve knob - Starves the CV signal, changing the pitch and increasing the chaoticness of the noise in mysterious ways. Fully clockwise is maximum voltage with no starve effect, turning it anticlockwise starves the circuit. Setting it just a tiny bit down from fully clockwise is often a good starting point for interesting sounds.

Touchpads - there are 6 touchpads which modulate the 6 oscillators. Each pad has 3 segments. The effect can be extreme or quite subtle depending on the knob settings, how dry your fingers are, finger position on the 3 segments, and which different pads you touch at once. They work best when the CV is slightly starved. You can also make contact between the pads with the ends of a patch cable. Do NOT touch them with a cable that’s connected to any jack of this or another module though, as this could possibly damage the oscillator chip!

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The module has been hand-soldered and tested by the designers, who are experienced synth builders.

This is the initial short-run black & silver edition of the Chernobyletta. This version has some minor reworking/modifications/rewiring on the pcb but is fully functional and these are not visible when racked of course. We also have a Black & Gold version operates and sound the same but has a black and gold panel and some minor cosmetic tweaks to the panel artwork and circuit. The Black & Gold version is available elsewhere and will be listed here soon, contact us if interested.

Technical specifications:
Panel Width: 20HP
Module Depth: 46mm
Power: +/-12v standard eurorack 10-pin connector, red stripe down. (Doesn't connect to 5v or signal rails)
Power consumption:
+12V: about 50mA
-12V: about 10mA