Electric Guitar Preamplifier
Here is the circuit diagram of a guitar preamplifier that would accept any standard guitar pickup. It is also versatile in that it has two signal outputs. A typ...
Dual Input-Combining Stereo Line Amplifier
This circuit takes two separate line-level stereo (L & R) signals and combines them into one stereo (L & R) output, thus avoiding the need to switch between two...
Cuckoo Sound Generator Circuit Schematic
This circuit generates a two-tone effect very much alike the cuckoo song. It can be used for door-bells or other purposes thanks to a built-in audio amplifier a...
Condenser Mic Audio Amplifier
The compact, low-cost condenser mic audio amplifier described here provides good-quality audio of 0. 5 watts at 4. 5 volts. It can be used as part of intercoms,...
Compact DJ Station
This project consists of a small, portable DJ mixer powered by a 9V dc external supply adaptor or from a 9V PP3 battery. The mixer features two stereo phono inp...
Bells Ring Generator Circuit Schematic
This circuit generates a dual-tone bells ringing similar to most door-bell units. It can be used in many applications other than door-bell. In the Notes below s...
Audio Power Meter
This simple circuit indicates the amount of power that goes to a loudspeaker. The dual-color LED shows green at an applied power level of about 1 watt. At 1. 5 ...
Audio Clipping Indicator
This circuit was intended to be used as a separate, portable unit, to signal by means of a LED when the output wave form of a particular audio stage is "clippin...
Antenna Input & Audio Lineout Adaptor For Portable Radios
Here is an idea for a simple low-cost adaptor that allows a portable FM radio (or MP3 player with FM tuner) to be connected to an external antenna and to audio ...
Accurate Bass Tone Control
A difficult problem in the design of conventional stereo tone controls is obtaining synchronous travel of the potentiometers. Even a slight error in synchrony c...
4 Channel Portable Audio Mixer
The target of this project was the design of a small portable mixer supplied by a 9V PP3 battery, keeping high quality performance. The mixer is formed assembli...
What is an Audio Mixer
If resistors R1 to R4 are variable, the signals can be mixed in any proportion, meaning at any volume levels. And overall volume can be set by a variable resist...
Talking Toy
You`ve probably seen many of these toys. They`ve been around for years, from the talking tickle me elmo to the talking furby, like the one shown above. How do t...
Vary the Volume of a Buzzer
This is a pretty simple project we are going to do. We are going to create a simple buzzer circuit where we can increase or decrease the volume of the sound tha...
Audio Mixer
In this project, we will build an audio mixer, which is a device that can add different audio signals together into one output. For example, say, one audio inpu...
Audio Equalizer
An equalizer is a device that allows you to adjust the gains of individual frequencies. You may want to lower bass, so on an equalizer, you would go to the freq...
Apply a Pulse to a Speaker Using a Capacitor
For this project, we`re going to demonstrate how a capacitor can supply a pulse signal to a speaker. We`re going to charge a capacitor and then discharge the vo...
Audio Level Meter
The circuit has a flat frequency response from about 20Hz to well over 50Khz. Input sensitivity is 100mV for a full scale deflection on a 100uA meter. Built on ...
Harmonics
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Pioneer CLD-1090
How to add an AC-3 RF output to older laser disc players. Finally I was ready to try it myself. Kevin Nakano`s web page (link below) was very helpful. His page ...