Tiptop Audio FOLD
Analog wavefolder with four sub-octave divisions
12 HP Eurorack module
The Fold Processor is a 100% analog wavefolder and subdivider module inspired by the Serge wave multiplier. It takes an input signal and folds it using a diode circuit, then feeds that folded signal into a square-and-divide circuit that produces sub-octave divisions spaced one octave apart. The result ranges from subtle harmonic enrichment to wild, pulse-width-modulated octave chaos depending on input type and knob positions.
Features
- 100% analog diode wavefolder circuit inspired by the Serge wave multiplier middle section
- FOLD knob with 0 to x6 gain range for progressive wavefold intensity
- INJECT knob for DC offset into the folding circuit, adding asymmetric harmonic variation
- CV input for FOLD with bipolar attenuator knob
- CV input for INJECT with bipolar attenuator knob
- Square and divide circuit converts folded output to four sub-octave signals
- Four subdivision gain knobs: divide by 1, 2, 4, and 8 (one octave apart each)
- Subdivisions mixed to SUBDIV OUT jack
- Folded signal also available separately at OUT jack
- Two audio inputs: IN 1 and IN 2
- Works with pure waveforms from VCO or self-oscillating filter for classic wavefolder use
- Works with complex signals like samples or drums for analog distortion effect
Controls & Jacks (14)
- Subdiv ÷4 — Gain control for the third subdivision output (÷4 octave)
- Subdiv ÷8 — Gain control for the fourth subdivision output (÷8 octave)
- Subdiv ÷2 — Gain control for the second subdivision output (÷2 octave)
- Fold — Controls the amount of diode folding applied to the incoming signal, ranges from 0 to x6
- Inject — Offsets the signal further to add more variations and harmonic content, with V and ^ markers indicating bipolar control
- Subdiv ÷1 — Gain control for the first subdivision output (÷1 octave)
- Fold CV Atten. — Attenuator for CV modulation of the FOLD parameter
- Out — Main output from the diode folding circuit
- Subdiv Out — Output from the square & divide subdivision circuit with all active divisions mixed together
- Inject CV Atten. — Attenuator for CV modulation of the INJECT parameter
- Fold CV — Control voltage input for modulating the FOLD parameter
- In 2 — Second audio input jack to the folding circuit
- Inject CV — Control voltage input for modulating the INJECT parameter
- In 1 — First audio input jack to the folding circuit
How-To Guides
- Classic Sine Wavefold
- Sub-Octave Layering
- Subdivision Chaos Sweep
- LFO-Modulated Wavefold
- CV-Controlled Inject Offset
- Analog Drum Distortion
- Fold-to-FM Feedback
- Z-DSP Delay Feedback Insert
- Fold Before Filter
- Dual Input Fold Mix
Explore the interactive FOLD panel on BleepDex — tap any control to learn what it does.
