Fuzzbox Physics
All Labs

CMOS Workshop

SIGNAL SOURCE
FREQ 220Hz
LOAD AUDIO
DROP FILE HERE or click to browse
VOLUME 35%
TOPOLOGY
CD4069UB × 2 · Rf=1MΩ · C=100nF
Red Llama — two self-biased CD4069UB inverters cascaded with 100nF coupling caps. Each stage has a 1MΩ feedback resistor that pulls its DC operating point to VDD/2 — audio swings around that midpoint and hits the S-curve soft corners. Drive pushes the first stage harder; the second stage rounds the already-clipped signal.
SUPPLY 9.0V
DRIVE 5.0x
BIAS +0.00
TONE 4.5k
1 INPUT BUFFER
IN
OUT
High-pass removes DC and sub-bass before the first inverter.
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2 INV 1 (GAIN)
PRE
POST
First CMOS stage — tanh S-curve rounds the peaks.
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3 INV 2 (CLIP)
PRE
POST
Second CMOS stage — full open-loop gain, signal slams into VDD rails.
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4 INV 3 / SCHMITT
PRE
POST
Third stage. Disabled in 2-stage topologies.
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5 TONE / OUTPUT
DRY IN
OUT
DC block + low-pass tone control. Blocks the bias offset, rolls off fizz.
Spectrum — Input (Clean)
Spectrum — Output (CMOS)