Build Your Own Superfast Polyphonic Octaver Pedal with DT-FOG Module

Introduction to DT-FOG Module Unlike other polyphonic octaver pedals those have significant latency, DT-FOG module produce octave and sub-octave with almost imperceptible latency. The DT-FOG module processes transient and non-transient signal components separately. This separation enable the transient processor to have superfast latency as low as 1/100 seconds (10 milliseconds), and the non-transient processor to have a good frequency resolution […]

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DIY Guitar Vocoder Pedal Using BWE-VO3 Module and GBPM-2 PCB

WARNING! As of August 30th 2023, BWE-VO3 module is discontinued (obsolete), replaced by DT-VO4 vocoder module. Refer to the following documents to build DT-VO4 Vocoder: DT-VO4 Vocoder Module User Manual DT-VO4 Application Note (BUILDING GUITAR VOCODER PEDAL USING DT-VO4 MODULE AND BGPM-2 PCB) Introduction BWE-VO3 is a vocoder effect module designed for guitar effect pedal application, based on digital simulation […]

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ESP32 I2S-PDM Interface for Digital Guitar Pedal Application

The PDM (pulse-density modulation) has been widely used in the current technology of audio signal conversion (from analog to digital) because its simplicity while achieving high quality conversion. This technology is widely used in digital microphone, and it is basically a sigma delta modulator circuit which is used in many modern audio codec chip as well. It is an interesting […]

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DIY Reverb Pedal Circuit: Spring-Hall Reverb with PT2399 IC

Introduction to Reverberation Before getting into the design of DIY reverb pedal circuit, lets see the concept of reverberation first. Real reverberation happens in a performance chamber when the walls and every object inside reflects the sound back and forth. As the sound bounces back and forth in three dimensional space, the reflections creates more and more complex pattern. The […]

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High Voltage (220VAC) Bass-Treble Automatic Disco Light Controller

The previous music-controlled disco light controllers, the audio-controlled disco light controller circuit and hi-lo (treble-bass) disco light controller have some features and drawbacks. The first one features high voltage drive, enable the circuit to drive 220VAC lamps, and the drawback is that it has only one way (single channel control). In the other side, the second version has two-way (bass […]

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Automatic Wah/Quack Effect Circuit with Attack and Decay Control

To get various characteristic of an auto wah/quack effect, we need a flexible control of  the envelope detection characteristic. Some playing styles need slow attack but fast decay,  but some others don’t. Employing the envelope detector circuit presented in our previous article [Ref 1], but with some modification to make it single supply operation. Here we present the improvement of […]

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Automatic Wah/Quack Effect Using LED+LDR Controlled Band-Pass Filter

Introduction to Automatic Wah/Quack Effect Automatic wah/quack effect gives a similar effect with the manual version (reference [1]), but without the need of any pedal to manually control the frequency/tonal sweep. This automation is made possible by detecting the envelope signal of the instruments audio signal, and use it to control the filter to produce center frequency  sweep, producing audio […]

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Inductor-less Wah/Crying Baby/Quack Effect Using Operational Amplifier

A type of guitar effect pedal that produce “wah”- or “quack”-like sound, which is similar to the crying sound of  a baby is called  wah-wah pedal, or just  wah pedal. The effect is produced by filtering the musical instrument through a band-pass filter, which the center of its peak frequency is swept from low to high, mimicking  audio tonal transition […]

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Fold-Back Distortion: Producing “Phew” Effect Using Software and Hardware (Analog Electronic Circuit)

Introduction: What is Fold-Back Distortion? I was introduced to a term of  “fold-back distortion” in the past by an article from an old book which I forget what the title is, but the book contains schematic diagrams of many circuits collected from old publication of Elektor magazine (www.elektor.com). The article presents the circuit’s schematic diagram and how it works. I […]

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Symmetric Distortion Using Clipper Diodes for Guitar Effect

Introduction While almost every audio equipments  pay whatever it cost to minimize distortion, this kind of device does the opposite: distortion effect for electric guitar. Many methods have been implemented in producing a distorted signal from electric guitar pick-up, such as over-driven vacuum tube, solid-state (transistor), or diode clipper. The simplest form is passive diode clipper, which is implemented as […]

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Hi-Lo (Treble-Bass) Disco Lamp Controller

Using high (treble) and low  (bass) frequency  beat detection to control stage lamps can produce automatic light jockey for disco or any music performance. Instead of using general level of music signal to control a disco lamp, the circuit presented here uses two separate channel to give more complex variation of light flashing pattern. The dynamics of music signal is […]

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Music Controlled Disco Light Circuit with Automatic Level Control

Introduction to Automatic Disco Light Control Simple audio or music controlled disco light uses comparator to sense the beat of a music signal, but this comparator has a reference point that should be calibrated according to the music signal volume. It’s easy if we have a light jockey to take the duty of controlling all the lighting, but it’s not […]

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