Low pass filter for Subwoofers
In the form it appears the theoretical circuit of filter. In first glance we see three different circuits that are mainly manufactured round two operational amp...
Volume Control circuit
Switch S2 is used for increasing and switch S3 is used for decreasing the volume. Similarly, switches S4 and S5 are provided for second channel (right channel) ...
Infrared Headphone Amplifier circuit
Using this low cost Project one can reproduce AUDIO from TV without disturbing anyone. It does not use any wire between TV and HEADPHONE. In place of pair of wi...
Graphic Equalizer circuit
This complete high quality, low noise 5-BAND GRAPHIC EQUALIZER circuit is based around Monolithic Linear integrated circuit LA3600 manufactured by SANYO. This c...
Mono to stereo audio generator
This circuit attempts to liven up mono sound sources by simulating a stereo signal. It does this by shifting certain frequencies between left and right to fool ...
Fuzz Guitar Effect circuit
Fuzz is one of the classic guitar effects, and this simple circuit generates it quite well. The circuit is so compact that it can be built into guitars or amps ...
Guitar phaser effect
This circuit is a phaser circuit, as used in guitar foot-pedal effects. It used 11 sections of op-amp such as LM324 but others will do. The whole circuit works ...
Audio 10 LED VU meter
The circuit was designed to work with an audio power amplifier which operated off +18v-0v-18v power rails. The actual voltage used is not too critical except th...
Polarity changer Switch
This project is useful if you wish to experiment with absolute phase, or are just interested in the possibilities of a polarity reversal circuit. In the case o...
Loudspeaker Tester
Testing loudspeakers is covered in some detail in the passive crossover article (see Design of Passive Crossovers), but it is irksome at best to have to fiddle ...
Active crossover circuit
A simple 3-way crossover, intended for triamping Hi-Fi systems. This is a conventional 12dB / Octave unit, and cannot be expected to have the same performance a...
Expandable Graphic Equaliser circuit
The project described in this article is a constant Q, fully expandable graphic equaliser. Where most "conventional" graphic EQ circuits have a Q that is depend...
Audio Mixer with preamplifier
The mixer is the common "virtual earth" mixing amplifier, and there is nothing special about it. Note that it is inverting, which complements the tone controls ...
HiFi stereo preamplifier with tone control
The preamp featured is very straightforward to make on the PCB, and has an innovative tone defeat function. Rather than completely disable the tone controls, th...
Subsonic audio Filter
The circuit shown is completely conventional. The Q of the filters has been optimised to allow a higher input impedance than would otherwise be possible, with t...
hi-fi Loudspeakers plans
The entire circuit is powered from a very simple regulated +-15V power supply, that is able to deliver about 2 A continuous duty, and at least 6 A on musical pe...
MIDI Program Changer
This circuit sends MIDI program changes. It's useful as a guitar pedalboard remote....
Phantom Wah for guitarists
This is an op-amp implementation of a Vox style wah, with the inductor replaced by a gyrator circuit. With the component values given the frequency response is ...
Guitar Flatline Compressor effect
This circuit is a simple, low noise guitar conpressor....
Rock Face effect for guitars
I've taken the classic Fuzz Face circuit and added optical temperature compensation. This ensures that the output stage is biased at half the supply voltage reg...