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Effects

How each major effect type actually works, circuit by circuit.

1
Fuzz
Fuzz is what happens when a transistor gain stage is pushed so far past its comfortable operating range that it stops scaling and starts flattening. This chapter covers the two circuits that define the whole category — the 2-transistor Fuzz Face and the 4-transistor Big Muff — and the input-loading quirk that makes fuzz behave unlike every other gain stage in this book.
2
Overdrive and Distortion
Overdrive and distortion both come from clipping a signal, but where the clipping happens — inside an op-amp's feedback loop or after a fully clean gain stage — is what actually separates the two categories, not gain amount. This chapter covers the Tube Screamer's in-loop clipping topology in full, then contrasts it with the post-gain clipping behind circuits like the ProCo Rat and MXR Distortion+ to explain why the two terms describe genuinely different circuits, not just different settings of the same one.
3
Delay
A delay pedal is a recording that plays back late — the entire category comes down to how the circuit stores that recording. This chapter covers the three ways pedals have done it: true analog BBD chips, the PT2399-style chip that sounds analog but is quietly digital inside, and a true digital delay's ADC-to-RAM-to-DAC path.
4
Modulation
Every modulation effect is the same idea applied to a different parameter: a slow, silent oscillator (an LFO) steers a knob for you instead of your hand. This chapter covers chorus, flanger, phaser, tremolo, and vibrato as one mental model with five different targets, plus the century-old Fender naming mixup that still causes confusion between tremolo and vibrato today.
5
Reverb
Reverb is what a delay effect becomes when you stop counting individual repeats and instead simulate thousands of them arriving so densely they blur into a continuous decay. This chapter covers the physical spring-tank mechanism behind classic spring reverb and the digital delay-network alternative that replaces springs with math.
6
Boost and Buffer
A buffer doesn't change your tone — it changes who's actually 'listening' to your guitar's pickups, protecting the signal from cable capacitance and a long pedal chain's cumulative loading. A boost is the same circuit with gain added. This chapter covers why both exist, why they're the simplest gain stage in this book, and the one common circuit — fuzz — that actively doesn't want one in front of it.
7
Compressors
A compressor doesn't add gain, distortion, or delay — it changes the relationship between a signal's loud and quiet parts, automatically turning the gain down above a threshold and back up as the signal falls away. This chapter covers the two circuit families that define the category — optical (LED/LDR) and VCA (OTA-based) — and the four controls, threshold, ratio, attack, and release, that every compressor design is built around.
8
Pedal Power Supplies
Reverse-polarity protection and daisy-chaining are covered on the wiring side in Assembly — this chapter covers the circuit-level power supply work that happens inside a pedal itself: charge pump ICs that double a 9V supply to 18V (or generate a negative rail) for extra headroom, and the LC filtering that keeps a noisy switching supply's whine out of the audio path.

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