Pedal Series

Three complete replica builds used to study how distinct analog topologies create gain, phase movement, pitch vibrato, and percussive amplitude modulation.

—100% analogTL072OTA phaser2N6027Metal enclosures

At a glance
Ownership	Independent fabrication, soldering, enclosure work, and assembly
Devices	Overdrive / preamp, phaser / vibrato, tremolo
Signal domain	Entirely analog
Key devices	TL072 op-amps, OTA phase stages, 2N6027
Controls	12 knobs, 3 toggle switches, 3 footswitches
Enclosures	Individual metal housings
Status	Three working effects

(01)Purpose

The series started from a practical musician’s need: I wanted several established guitar effects, so I built them. Reproducing proven designs turned acquisition into an engineering study—reading each circuit as a system, assembling it cleanly, packaging it for foot operation, and hearing the behavior of each topology in a finished device.

Together, the three pedals create a compact analog laboratory. The preamp shapes gain and tone; the phaser manipulates phase relationships and can remove the dry path for true pitch vibrato; the tremolo controls amplitude with a sharp, repeat-percussion waveform.

(02)Three circuitsGain / phase / amplitude

A / Overdrive

Overdrive Preamp

Victory Kraken V1 replica

Two gain stages built around TL072 dual op-amps
High-gain “amp in a pedal” response
Gain plus three-band EQ
Range from mid-gain to heavy British- and American-style voicing
100% analog signal path

B / Modulation

Phaser / Vibrato

EarthQuaker Devices Grand Orbiter replica

Four-stage OTA-based phaser
Three-way rate range from slow sweep to fast swirl
Depth, resonance, rate, and sweep control
Two-way phase / vibrato switch removes the dry signal for true pitch vibrato
100% analog signal path

C / Modulation

Tremolo

EarthQuaker Devices Hummingbird replica

Transistor-based circuit featuring a 2N6027 device
Choppy sawtooth amplitude modulation
Vintage repeat-percussion character inspired by Valco and Vox amplifiers
Three rate ranges from slow pulse to helicopter-like speed
100% analog signal path

(03)Technical reading

Gain architecture

The preamp uses two TL072 stages to generate the saturation and level required for a convincing high-gain amplifier character. A three-band tone network makes the result adaptable to different guitars and host amplifiers rather than locking it to one fixed voice.

Phase architecture

The modulation pedal moves the signal through four OTA-controlled phase stages and recombines it with the dry path to create cancellation notches. Removing that dry path changes the perceived result from phasing to pitch vibrato—two related effects exposed through one circuit.

Timing architecture

The tremolo produces a sawtooth-style control waveform around a 2N6027-based circuit. Three switched rate ranges give the same core oscillator dramatically different musical roles, from a slow vintage pulse to a highly percussive chop.

(04)Hardware studyOne photograph / three functional crops

High-gain overdrive preamp pedal — Fig. 01 — PreampTL072 / 5 controls

Four-stage phaser and vibrato pedal — Fig. 02 — Phaser / vibratoOTA / dual mode

Sawtooth tremolo pedal — Fig. 03 — Tremolo2N6027 / 3 ranges

Three familiar sounds became three lessons in analog behavior.

Building the effects as finished pedals made the circuitry tangible: gain structure, phase cancellation, oscillator range, switch logic, noise, wiring, and mechanical layout all become audible parts of the result.