Audio circuits to build

The following links to circuit diagrams and building projects I have found from other web sites. I have tested only very few of them so there is no guaratee that those circuit will work as expected. I don't have more info on those projects than what you can download from those sites which have the circuits. If you have more questions about those circuits then please mail the questions directly to the person who has designed the circuit or to the people responsible for those web pages.

Index

Project link pages
Amplifiers
Audio controlling circuits
Building microphone
Crossovers
Compressor/limiter
Design ideas
DI-box circuits
Differential input and output circuits
Digital audio circuits
Equalizers and filters
Guitar effect boxes
HiFi preamplifers
Measuring
Microphone preamplifiers
Misc effects
Mixers circuits
Other preamplifiers
Preamplifiers
Tube amplifiers
Vocal elimination

Project link pages

Andrea's projects - circuits and documentation
Audio circuit at Digital Music Zone - compressors, effects, preamps, microphones, phantom power
Digital Music Zone Schematics - compressors, microphones and effects
DIY Audio pages
Power amplifiers
- Low power (<30W)
  - 10 Watt IC Power Amp - based on TDA2030
  - 20 Watt IC Power Amp - based on LM1875
  - 22 Watt Audio Amplifier - simple stereo amplifier based on TDA1554
  - 8 Watt Audio Amp - based on LM383
  - Audio Amplifier - single chip 2W amplifier that runs on 5 Vdc to 15 Vdc, based on TBA 820M
  - Cheap 10 W amp - based on TDA2003 IC
  - Cheap thingies to help you make some racket - small amplifier circuits using many amplifier ICs, from few watts to 200W
  - Hiraga Le Classe A -20W
  - Lidström Improved ZEN i - class A FET amplifier
  - Low Power Audio Amplifier - based on LM386
  - New Audio Amplifiers with Current Amplifier Outputs - basic 10W design, other designs up to 75W
  - Class A Amplifiers - a 10W design by J. L. Linsley Hood, check also A Simple Capacitance Multiplier Power Supply For Class-A Amplifiers
  - Single-transistor amplifier (joke)
  - The 2-Channel Power Amplifier: Design and Testing - 4W amplifier based on NTE 1606
  High power (>30W)
  - 100W RMS Amplifier - also available in compressed tar format
  - 50 Watt Amplifier - easy to build general purpose 50 watt amp
  - 68-Watt Power Amplifier - Experimential power amplifier using the low-cost LM3886 monolithic power amp IC
  - 90-watt RMS Audio Power Amplifier - Quasi-complimentary power-output stage for an audio amplifier, experimental design that is not intended for practical use
  - Cheap thingies to help you make some racket - small amplifier circuits using many amplifier ICs, from few watts to 200W
  - Mosfer Amplifier 230W / 400W
  - New Audio Amplifiers with Current Amplifier Outputs - basic 10W design, other designs up to 75W
  - Pass Laboratories DIY Projects - many amplifier projects
  - SDS Labs Schematics - solid state class A amplifiers
  - Stereo Cassette Player - 150W audio amplifier circuit, complete with stereo pre-head amplifier and bass-treble control section
  - Symmetrical Output Amplifier - FET amplifier with power rating of 230 Watts RMS into 8 Ohms Per Channel and 400 Watts RMS into 4 Ohms Per Channel, first published in Silicon Chip Magazine in June 1994
  - The Leach Amp - 120W power amplifier, latest update of the "Low TIM Amplifier", claimed to be a very good sounding design
  - The Leach SuperAmp - 270 watt Double Barreled Amplifier published in Audio magazine
  - The LM12 Amp - 80W amplifier based on LM12 IC
  - Zen Amp and Preamp
  Professional audio amplifier circuit diagrams
  - Professional Sound Systems has full circuit diagrams of some of their PA amplifiers in their technical pages, power ratings from 2x80W to 2x400W
  - QSC Audio has service manuals and circuit diagrams of some of their amplifiers on-line
  Car amplifiers
  - 5 Channel Current FB Car Amps - 200W current feedback amplifier design
  - 20 Watt Power Amplifier
  Power amplifier accessories
  - Loudspeaker Protection circuit - DC protection circuit
  - Power Follower with Dinamic Current Source by Reinhard Haffmann - less wasted power than true class A but not as good sound
  Headphone amplifiers
  - HeadBanger Headphone Amp Construction Kit
  - SDS Labs Headphone Amp - solid state amplifier
  - Stereo Headphone Box - takes input from one audio power amplifier and drives many headphones vith adjustable audio level, available as a kit from Sescom
  - A HREF="http://www.headwize.com/projects/ciuff_prj.htm">Top-Level OTL Tube Headphone Amplifier
  Preamplifiers
  - A low distortion audio preamplifier
  - Audio Preamp - simple preamp for electric guitar or microphone
  - Hiraga MC -Moving Coil förstärkare
  - Kaneda Linjeförsteg - includes phono and line inputs
  - Mic-Pre Pan Pot Circuit
  - Simple Guitar Preamplifier
  Application notes and datasheets
  - Cool Audio - Harris application note on PWM amplifiers
  - LM12 - very compact IC for making good quality 80W audio amplifier, this IC has been used in some high quality active loudspakers
Tube amplifiers
- 25L6 Amp - design with out a power transformer
- Ampage - tube amps and music electronics
- Build a tube amplifier - articles from HiFi magazine (in Finnish)
- Dynaco Mark 3
- Dynaco stereo 70
- Homebrew Tube Amp Corner - FAQs and circuits
- Klassiskt 300B slutsteg
- >Klaus Schiffer's audio web site - tube amplifiers and tube information
- KTA/KSA High End Tube Audio - many tybe amplifier projects
- Musical Instrument Tube Amp Building, Maintaining and Modifying FAQ
- SDS Labs Schematics - solid state class A amplifiers, headphone amplifier, vacuum tube amps
- Sheldon's Audio Designs - audio DACs and tube amplifiers
- Soft start for power tubes
- Tube Microphone Preamplifiers V72 (Telefunken/Siemens/Maihak/TAB) - information about the amplifier and the schematic
- Vacuum Tube Amplifier Construction Articles at the engineering musician webmagazine - articles targeted at preamplifier design and construction
- Vintage Quad equipment circuit diagrams
- Quad 22
- Zero Feedback Stereo Pre-Amplifier with Balanced & Unbalanced Inputs and Outputs
Mixers circuits
- Audio mixer for Ramsey FM10 transmitter: schematic and description, schematic also in Postscript format
- Circuit Central Library - include 4 channel mixer circuit
- Dual Booster - two op-amp drives switchable to one output
- Simple 4-input mixer
- Simple audio mixer for two signal sources
- Simple audio mixer design ideas
- Transistorized Audio Mixer
Differential input and output circuits
- Input
  - Additional RFI Protection for Line Input Circuits - 8KB PDF
  - Instrumentation or true balanced input differential amplifier
  - Jensen Transformers Application Notes and Schematics - many circuit examples with transformers
  - Making Differential Probes - for sensing audio signal voltages across devices which are not ground referenced
  - Simple differential amplifier - opamp balanced input circuit with unity gain and common mode rejection adjust
  Output
  - Non-inverting amplifier - opamp circuit which provides 15 dB gain and option for balanced output
  - Simple 0 to 24 dB Gain Amplifier and Balanced Line Driver - 18KB PDF
  Input and output in same circuit
  - Balanced Line Technology - information and example circutis for both input and output
  - Circuit Central Library - balanced input and output circuits
  - Quad Buffer - gives 4 Isolated Outputs
  - Zero Feedback Stereo Pre-Amplifier with Balanced & Unbalanced Inputs and Outputs - tube circuit
  Other circuits
  - Long Lines Driver - high current output configuration is ideal for use as a transformerless long lines driver
DI-box circuits

Circuits for helping to interface electronic music instruments to mixing desks. The main goal of a DI Box is convert the usualy high impedance output of an instrument (usualy a guitar pickup) in a low impedance ouput to feed a mic input of a console. Balancing the signal is important if you want to use the mic input. Ground isolation is a plus.
- 10 to one voltage divider for direct input - very simple DI-box idea for your guitar amp output
- Black Box Circuit - a 40dB pad/100:1 attenuator for running spaker output to DI-box, so if you put 100 Watts in you'll get around 275 mVolts out
- Jensen Direct Box Transformer - data sheets have example circuit diagrams
- PO-26 Passive Direct Box - circuit diagram of Sescom PO-26 kit
- PO-25 Kit 1 x 3 Mic Splitter - circuit diagram of Sescom PO-25 kit
Microphone preamplifiers
- Audio preamplifier circuits - three transistor microphone preamplifiers
- A Vacuum Tube Microphone Preamp / Direct Box Project - from January 1997 EQ Column, includes phantom power supply
- Balanced mic/line amp with TUBES - uses two 12AU7 tubes in a class-A cathode-driven input stage, followed by a class-AB1 cathode follower output stage, 6db gain, requires 90VDC and 12VDC
- Balanced Mic Preamp - based on SSM2017 and has option for 48V phantom power
- Condenser microphone hookup
- Dual Phantom Power Microphone Preamplifier - information and full schematic of a kit available from PAiA Electronics, take also look at the circuit diagram
- IC mic preamp uses Jensen Twin-Servo topology
- Jensen Transformers Application Notes and Schematics - many microphone preamplifier related circuits
- JT-13K6-C in Simple One IC Stage Mic Preamp - 15KB PDF
- Kondensaattorimikrofonin esivahvistin - simple preamplifier for electret microphone, text in Finnish
- Mic-Pre Pan Pot Circuit
- Modern Microphone Preamplifiers - A paper originally published in R-E-P Magazine, cintains general information but does not contain circuit diagrams
- Microphone and general purpose preamplifier - amplification of up to 1000 times
- PAiA Tube Mic Preamp
- Simple microphone preamplifier - simple one transistor circuit
- Standard Microphone Preamplifier Input Circuitry - pdf file
Building microphone
- Binaural Microphone System for Minidisc recorders
- Build a pair of binaural microphones
- Electret MIC Apps - an electret MIC is the best value for money omnidirectional microphone you can buy for 90% of microphone application
- Electret microphone connection - how to connect electret microphone
- Electret microphone powering circuits
- Homemade Binaural Mics
- Interfacing Microphones to Computer Sound Cards
- Making a rugged, connectorized microphone from a Panasonic microphone capsule
- PZM Modifications - phantom powering electret microphone capsule
- Schematics of old tube mics
- The Electret Condenser Microphone - simple basic connection diagrams
HiFi preamplifers
- Phono Preamp - tube design
- Phono premaplifier - RIAA two-pole filter curve and its implementation using operational amplifier
Other preamplifiers
- The ampage schematic collection - guitar and bass preamplifiers
Audio controlling circuits
- Digital Volume Control
- VOLC - this tar file consists of the schematic for a digital audio control
- Voltage controlled amplifier - three different circuits
- Voltage Controlled Audio Panner - variable gain amplifier circuit
- Voltage-controlled stereo signal attenuator
Filters and effects
- Equalizers and filters
  - 10 band audio equalizer - ascii drawing of simple circuit
  - High-Q, 60-Hertz Notch Filter - very high-Q and narrow notchband
  - Active Filters - Butterworth, Bessel and Linkwitz filter example circuits and equations
  - Audio Graphic Equaliser - simple 7 band equalizer
  - Basic gyrator design - basic building block of graphic EQ
  - High-Q 60-Hertz Notch Filter - pdf file
  - LMC835 - Digital Controlled Graphic Equalizer IC, take also look at application note
  Crossovers
  - 24db/octave Linkwitz-Riley
  - 3-way 4th Order Active Crossovers for Car Audio
  - Subwoofer filter - 12 dB/octave low pass filter for subwoofer, includes subsonic filter
  Compressor/limiter
  - Compressor using photoresistor - very basic circuit based on LED, LDR and OPAMP
  - Dynacomp compressor
  - Opto limiter - check also redrawn schematic
  - Q&D Compressor - A complete guitar compressor/limiter design based on SSM2165, check also HTTP://members.aol.com/jorman/schem.html for infor where to get the compnent
  - Stereo Broadcast Limiter Circuit for the Ramsey FM10a/FM25 transmitter - also available in Postscript format
  - Tape saturator - Schematic of analog tape compression circuit, read also circuit description
  - Urei LA-5 Audio Leveler - from Dan Fraser's Home Page
  Guitar effect boxes
  - Distortion Effect (for guitars) - three distortion circuit ideas
  - Distortion effect for guitars
  - Guitar Effects Boxes - guitar effect schematics and articles
  - Guitar-related Circuits - effect circuit collection
  - Harmony Central - contains effect information, schematics and construction tips
  - LXH2 "Marshall" simulating preamp circuit - read also the description
  - LXH2 Web Page - guitar amplifier and cabinet simulator circuits
  - Phase Shifter - The classic, swishy sound of the 70s and 80s is coming back, provides a 0 to 180 degrees of phase shift, with a variable sweep control, for keyboards and guitar
  - PracticeMan(TM) - battery powered small guitar amplifier with distortion and tone controlls
  - Stage Center Reverb Unit - simple spring reverb unit
  - The Guitar Effects Oriented Web Page - FAQs and circuit diagrams
  - The LXH2 Web Page - guitar box simulator information
  Vocal elimination
  - CD Buddy - Karioke device
  - How to filter out voice in music - very simple method
  Misc effects
  - Burwen audio processor documentation - dynamic noise filter and eliminator circuit diagrams
  - Digital Potentiometers Overview - information about digitally-controlled solid-state electronic potentiometers from Dallas Semicondictor
  - lxh2 spatialization circuit
  - Mixed feedback drive circuits for audio output transformers - technical paper from Lundahl Transformers in pdf format
  - Noise generator - generates white and pink noise, from Synth Fool
  - Square wave to sine wave converter circuit
  - SSM ICs datasheets - voltage controlled amplifers etc.
  - True bypass DPDT switching - produce true bypass when effect is switched off
Digital audio circuits
- S/PDIF
  - CD-ROM to MD - get toslink signal from your CD-ROM drive
  - Cheap TOSLINK Transmitter
  - Coax Digital Out to MD - Convert the coax signals to TTL signals for Toslink module
  - Optical output for Creative Infra CD-ROM - little circuit to connect your MD or DAT to your CD-ROM drive with standard optical S/PDIF cable, based on TOTX173
  - SPDIF Circuits - input and output interfacing circuits
  - S/P-DIF I/O Using the Epoch SoundPro HT-1869V+ Card - circuits for S/PDIF to TTL interface and TTL to S/PDIF coax
  SCMS
  - A SCMS killer circuit - should work with all DAT decks that have a Sony CXD2601 signal processor, published in September 1992 in "Stereoplay", also available at ftp://ftp.cs.ruu.nl/pub/MIDI/DOC/pbscms.html
  - Copybit deleter - sets the copybit in digital audio signals to enable copying of digital recordings
  DAC
  - Audio Crafters Guild Articles & Essays - DAC building articles
  - DAC v1.1 - high-performance DAC using the Crystal Semiconductor 8412 receiver, 8x oversampling, Burr-Brown PCM1702 D/A chips and the POOGE-5 output stage
  - Jitter-Free DAC
  - JT-DAC No. 3
  - SDS Labs DAC Page
  Equipment modifications
  - CDplayer's Project - information to make and upgrade a CDPlayer at home
  Misc
  - CrystalClear AC'97 AMR Audio Modem Riser card reference design
  - Electronic bell - Plays 2 mono 8bit wav files, stored in EPROM
  - Heiko's DAT Page - D-7 connections, DAT error counter, SCMS, IR controlling
  - Sample Rate Converter Project - inputs an s/pdif (or AES/EBU) signal between 25 and 50kHz, and outputs an s/pdif signal at 44.1kHz
Measuring
- Audio LED VU meter - built around discrete components
- A-weighting filter
- Building the L-R Test Set - helps you to set up left/right channel balance on audio broadcasting ystems
- LM3915 Dot/Bar Display Driver - suitable for VU meters etc.
- LM3916N bar graph driver - datasheet in pdf format, drives a 10 LED bar graph with VU proportions (3dB/step)
- Peak Power Indicator - a very simple circuit for an LED indicator that blinks when the delivered power to the amp exceeds a preset amount
- Peak Reading Level Meter Using Indicator Tubes
- Sound Level Meter - one chip replacement for the standard analog meters, based on LM3915 audio level IC
- VU Meter Amplifier
- VU Stereo Meter - will indicate the volume level of the audio going to your speakers by lighting up LEDs, based on LM3915 IC
Design ideas
- Analog Devices Practical Analog Design Techniques Seminar - seminar papers on web
- Ask the Applications Engineer - a collection of articles from its "Analog Dialog" newsletter in pdf format from Analogue Devices, useful info for people designing aDC and DAC systems
- Analog record and playback IC's
- Circuit Central Library - lots of audio circuits
- Determining Output Transformer Impedance - When replacing the audio output transformer on a radio, the replacement should match the impedance of the original as close as possible
- Digital Volume Control - based on DS1669 Digital Pot IC
- Dual +/- 15 volt power supply - suitabe for powering many opamp circuits
- Guitar Effects FAQ
- Jensen Transformers Application Notes and Schematics
- Known WWW Tube and Audio Internet Sites - checl alse the second page
- Main principles of amplifier wiring - how to wire operational amplifier circuits
- Mosfet Power Amplifiers - A discussion of the benefits of the lateral Mosfet output devices used in todays High Power audio amplifiers
- Proper Grounding Inside Equipment Avoids Ground Noise Coupling (aka"Pin 1 Problems") - 15KB PDF
- Sheldon's Audio Designs - audio DACs and tube amplifiers
- Subtleties count in wide-dynamic-range analog interfaces - transporting high-dynamic-range analog signals from one piece of equipment to another is not a trivial task, design article from EDN magazine
- Tube to FET Mod - onverting tube radios, the 5 tube AC-DC type to Solid State
Misc circuits
- Andrea Ciuffoli Document Page -
Module and kit reviews
- The BK Power Amps - amplifier modules from 100W to 1kW

Back to electronics home page

If you have any suggestions, please let me know : Benny_V@USA.net.

web hosting • domain names • video sharing
free online games • photo sharing
free blog • short URLs