Free Electronic Circuit Design
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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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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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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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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Introduction to Envelope Detector Circuit Envelope detector circuit is used to get the amplitude profile of a signal. Some important properties of an envelope detector are attack or rise time and decay or release time. In the Figure 1, a signal is plotted in blue, and the detected envelope is plotted in black. Since it employs capacitor for filtering inside […]
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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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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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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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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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The microphone pre-amplifier circuit described here make the microphone sensitive to a sound come from very close source, and insensitive to any sound coming from far sources. This works even when the far sound is very loud. The main application of this circuit is in telecommunication system like in mobile phones, where the microphone should pick a clear speech even […]
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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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