An upright glossy blue box photographed face on, OCTAVE hand-lettered in pale green across the top and AVALANCHE running down the right edge. Two light blue knobs with numbered skirts, lettered TONE and VOLUME, sit one above the other on the left, seven chrome toggle switches run down the right, and at the bottom there is a toggle on the left and a small round bezel on the right.

Seven octaves on seven toggles · Clean Boost inside · One of a kind

Octave Avalanche

Synth Available · 1 of 1

My Octave Avalanche in a blue 125B: seven square waves an octave apart, each on its own toggle, all mixed into one output. It sounds like a soundtrack being played backwards. It is a quiet circuit, so my Clean Boost rides inside to give it some gain.

TypeOctave divider synth, two of my boards in one box
ControlsTwo knobs, TONE and VOLUME, seven toggles down the right side and one more at the bottom left
CircuitMy Octave Avalanche layout, with my Clean Boost inside for gain
Enclosure125B
Weight~8 oz
Power9V DC, center-negative barrel jack
BuiltOctober 2026
StatusAvailable - one of a kind

$80 free shipping Email to Buy

What it does

Both boards are layouts I give away on this site: the Octave Avalanche and the Clean Boost. The Octave Avalanche divides one oscillator down through a CD4040, so each toggle brings in the same note at a different octave, and the stack piles up into one wall of sound. The Clean Boost is one transistor of gain after it, because on its own the circuit comes out too quiet for my taste.

Demo

Demo video coming soon.

Controls

The seven toggles: One octave each. Flip them in any combination; the more that are up, the bigger the stack.
The two knobs: TONE and VOLUME, lettered on the caps.

Circuit: my own Octave Avalanche layout, free on this site, with my Clean Boost inside for gain. Built, painted, and finished by Onion Madder as an original one-off - not affiliated with, endorsed by, or a clone of any commercial brand.