AUDIO CIRCUITS and PROJECTS
2 Watt Amplifier
- A 2 Watt audio amplifier made from discrete components. This amplifier has a S/n ratio of 115dB at 1kHz.
TDA2030 8w Amplifier
-An 8 watt amplifier project made with the TDA2030 IC. Built two such units for a stereo amplifier circuit.
Tone Control Circuit
-Based on the classic Baxendall tone control circuit, this provides a maximum cut and boost of audio around 10dB at 10K and 50Hz.
ECM Mic Preamplifier Project
-A microphone amplifier that may be used with either Electret Condenser Microphone (ECM) inserts or dynamic inserts, made with discrete components.
stereo line driver
-A stereo line driver for feeding long cables or buffering an audio source.
Notch Filter Circuit
-A variable notch filter circuit with both high and low pass filters.
6 Input Mixer
-A simple mixer with 3 line inputs and 3 mic inputs using commonly available parts.
The mixer circuit above has 3 line inputs and 3 mic inputs.
Hi-Fi Pre-Amplifier Circuit
-This circuit was submitted by Graham Maynard from Newtownabbey, Northern Ireland. It has an exceptionally fast high frequency response,as demonstrated by applying an 100kHz squarewave to the audio input.
Peak Reading Audio Level Meter
-Using a single Mosfet Op-amp this circuit samples the audio input and displays peak readings.
Doorphone Intercom
- A simple 2 way Intercom project based on the LM386386 using 8 ohm speakers.
Computer Microphone
- The sound card for a PC generally has a microphone input, speaker output and sometimes line inputs and outputs.
100 Watt Audio Amp Circuit
-simple amp project to make
3 Band Equaliser
-A tone control circuit made with a single op-amp and having three ranges, bass, middle and treble controls.
Voice-Over Circuit
-This is a circuit where a microphone and preamp circuit (voice circuit) have priority over any other audio signal. You can think of this as a one way intercom, if the main amplifier is used for listening to music, then when the push to talk switch is pressed, the amplifier is switched to the voice signal.
Quadraphonic Audio Amplifier
-This is a four channel amplifier ideally suited for use with quadraphonic equipment such as a Sound Blaster Live card. There is no volume control,audio levels being directly controlled from the sound card itself.
15 Watt Audio Amplifier
-A 15 watt amplifier made using discrete component parts. Sergio designed this circuit for his Electronics Level II course.
Audio VU Meter
-This circuit uses two quad op-amps to form an eight LED audio level meter. The op-amp used in this particular circuit is the LM324. It is a popular IC and should be available from many parts stores.
Soft switching Amplifier with Tone Controls
-Built around an LM380, this amplifier includes tone controls and electronic "soft switching". The soft switching circuitry ensures power is built up gradually eliminating the dc thump.
Audio Level Meter
-Audio levels can be monitored using a small panel meter with this circuit built from discrete components.
Dynamic Microphone Amplifier
-A low noise pre-amplifier suitable for amplifying dynamic microphones with 200 to 600 ohm output impedance.
Headphone Amplifier Porject
-An amplifier to drive low to medium impedance headphones built using discrete components.
Low Voltage Audio Preamplifier
-A low voltage preamplifier optimised for 3 Volt operation.
Class A//A-B 100W Amplifier
-A Class A // Class AB amplifier rated 100 Watts when driving a 4 ohm loudspeaker.
Vinyl Amplifier
-pre-amplifier circuit. It remains capable of optimising disc playback and offers features still not repeated today.
Op-Amp Microphone Preamplifier
-A high quality microphone preamplifier using a single power supply, suitable for dynamic or electret microphones. The opamp used can be any low noise, high performance type, e.g. NE5534,TL071, OPA 371 etc
Buffer Amplifier
-A hifi preamplifier designed to convert high output impedance amplifiers to 600 ohm outputs.
The Gem Amplifier
-The GEM is an audio power amplifier embodying simultaneously active Class A and Class AB output stages for 100+ Watts into a 4 ohm loudspeaker. The front end pcb will drive up to 100+W variants, or the 200+ Watts version into a 4 ohm loudspeaker load.
150W MP3 Car Amplifier
-LF353 Wide Bandwidth Dual JFET Input Operational Amplifier
General Description These devices are low cost, high speed, dual JFET input operational amplifiers with an internally trimmed input offset voltage (BI-FET II technology).
24 Watt Class A Amplifier
-A 24 Watt Class A Amplifier made from discrete semiconductors, built and tested by Marc Klynhans from South Africa.
Mini-MosFet Audio Amplifier
- This project was a sort of challenge: designing an audio amplifier capable of delivering a decent output power with a minimum parts count, without sacrificing quality.
18 Watt Audio Amplifier
-Can be directly connected to CD players, tuners and tape recorders. Do not exceed 23 + 23V supply.
25 Watt MosFet Audio Amplifier
-Can be directly connected to CD players, tuners and tape recorders. Simply add a 10K Log potentiometer (dual gang for stereo) and a switch to cope with the various sources you need. Q6 & Q7 must have a small U-shaped heatsink.
60 Watt MosFet Audio Amplifier
-High Quality, powerful unit: 90W into 4 Ohm Also suited as guitar or bass amplifier
10W Audio Amplifier with Bass-boost
-High Quality, very simple design No need for a preamplifier
Mini-box 2W Amplifier
-Designed for self-powered 8, 4 & 2 Ohm loudspeakers .Bass-boost switch
3 - 5 Watt Class-A Audio Amplifier
-Behaves like a one-valve operated amplifier. Simple circuitry - No cross-over distortion
Modular Audio Preamplifier
-High Quality, Discrete Components Design. Input and Tone Control Modules
Phono Preamplifier
-Simple circuitry suitable for moving-magnet cartridges. Passive high-frequency equalization
Stereo Preamplifier with Bass-boost
-High Quality, simple design. 20 to 30V supply
Automatic Loudness Control
-Simple add-on module. Switchable "Control-flat" option
Portable Microphone Preamplifier
-High headroom input circuitry. 9V Battery powered
Headphone Amplifier
-High Quality unit. No need for a preamplifier
Portable Headphone Amplifier
-3V Battery powered High Performance unit
Portable Mixer
-High-quality modular design. 9V Battery powered - Very low current drawing
Three-Level Audio Power Indicator
-Battery-operated 3 LED display.Simply connect it to loudspeaker output
Six-LED Bar Power Indicator
-Useful to monitor audio power delivered to loudspeakers. No power supply - no setup required
Precision Audio Millivoltmeter
-Measures 10mV to 50Volt RMS in eight ranges. Simply connect to your Avo-meter set @ 50µA range
Sound Pressure Level Meter
-Suitable for home-cinema setup. 9 Volt operated portable unit
1KHz Sinewave Generator
-Simple circuitry, low distortion, battery operated.Variable, low impedance output up to 1V RMS
Low-distortion Audio-range Oscillator
-Generates very low-distortion sine waves up to 1V RMS.No thermistors required - No settling time
Simple Squarewave Generator
-Three switchable frequencies: 100Hz, 1KHz, 10KHz. 1.5V battery operated, minimum parts counting
Self-powered Sine to Square wave Converter
-Converts sine to square waves without a power-source. Useful as a test instrument for audio purposes
Amplifier Timer
-Turns-off your amplifier when idle for 15 minutes.Fed by amplifier tape-output
Amplified Ear
-Useful to listen in faint sounds. 1.5V Battery operation
Full-duplex Intercom
-No complex switching required. Simple circuitry, 6-12V supply
Telephone call Voice Changer
-Voice manipulation device specially intended for props. 9V Battery operation
Intercom with fader
-Suitable for tandem bicycles and motor cycles.Connects to iPod and similar MP3 audio players
Mini Mixer
-Small portable device - 9V battery operation. Three high/low-sensitivity switchable inputs
Portable 9V Headphone Amplifier
-High Quality One-IC unit. Low current consumption
Speech Amplifier Box
-Small portable device - 6V battery operation. Suitable for teachers, lecturers, tourists' guides etc.
Audio Clipping Indicator
-Detects clipping in preamp stages, mixers, amplifiers etc. Single LED display - 9V Battery supply unit
Pure Class-A Headphone Amplifier
-400mW RMS into 32 Ohm load Single-rail Supply - Optional Tilt Control
Battery-powered Headphone Amplifier
-Low distortion Class-B circuitry. 6V Battery Supply
Compact DJ Station
-Two Phono/Line switchable inputs. Powered by 9V Battery or external supply Adaptor
Car Subwoofer Driver
-22W into 4 Ohm power amplifier. Variable Low Pass Frequency: 70 - 150Hz
Audio Mixer - Transistorized-Other features can be added to this basic mixer. One or more
microphone preamps could be added. A VU level meter or LED bargraph
can be added.