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120VAC Touch Switch - This is a capacitance based touch on/touch off switch,
which can control power to a 200 watt 120vac load.
2 Line Output Combiner - Convert consumer equipment stereo signal to mono or
combine audio signal from two different equipments to1-input.
2-Way Electronic Crossover - Conventional 3rd order electronic crossover
24 dB/Octave 2/3-Way Linkwitz-Riley electronic crossover - Linkwitz-Riley
alignment. This is a very nice crossover, Rev-B boards now available
3 Channel-Color Organ - An old ideabut I've had numerous requests for a good
design for this....
3 Level Audio Power Indicator - Battery-operated3 LED display that connect
it to loudspeaker output
3-Way 12dB/ Octave Crossover - Contributed project, simple 12dB/ Octave
crossover network.
30 Ddm to +30 Ddm Audio Level Meter - circuit with balanced input and
adjustable gain to drive needle type VU meter, uses special amplifier module
from Op-Amp Labs
300 Watt Subwoofer Power Amplifier
48V Phantom Supply - Low noise 48V regulator and phantom mic supply
circuits.
A DC-Coupled, Selectable-Gain Headphone Amplifier - This design uses two
opamp gain stages per channel for superior input buffering and a discrete
bipolar output stage with thermal tracking current mirrors. The amplifier's
overall gain can be adjusted to match the efficiency and impedance
characteristic of any headphone.
A Musical Distortion Primer - This is an introduction to the basic means of
distorting a signal in a musically useful way. The approach is as non-technical
as possible. I use the simplest signal waveform, a sine wave, to illustrate all
these, although a guitar is much more like a sawtooth than a sine wave. The
clipped waveforms will be shown in their raw state
A Reader's Xover - This is well worth reading if you can't decide on
biamaping
A Soundfield Simulator for Stereo Headphones - An adaptation of the Linkwitz
acoustic simulator (see An Acoustic Simulator for Headphone Amplifiers by Chu
Moy above) as a front-end for headphone amplifiers with very high input
impedance, such as the author's own headphone amp project (see A DC-Coupled,
Selectable-Gain Headphone Amplifier). This circuit features a continuously
adjustable Soundfield control. Designed by Chester Simpson
A-B Switch Box - Can you really hear the difference between amps or cables?
ABX Comparator - Full ABX testing unit, without microcontrollers or a PC
Active Subwoofer & Controller
Add headphones to a Class D Amplifier - EDN Connect headphones to the
MAX9704 and make a quieter lab or office
Add on Stereo Channel Selector
Amplificateurs audio - en Français
Amplifier Phono Input as Line Level Input
Amplifier Thermal Protection
An Equalization Circuit for the beyerdynamic DT990 Pro Headphones - This
passive EQ corrects a rising characteristic in the frequency response of the
beyerdynamic DT990 Pros and turns them into one of the most natural and accurate
sounding headphones on the market. Designed by LXH2
AN215: CS4201/CS4202 Headphone Jack Sensing using GPIO
Analog Synth Keyboard Schematic
Anti-RIAA Equalizer for Line to Mag Phono Converter - AS071 Jenson
Transformer Application Note
Arc welder sound simulator
Audio Amp Output Power Limiter
Audio Amp Timer - Turns-off your amplifier when idle for15 minutes Fed by
amplifier tape-output
Audio Amplifier Output Relay Delay - This is a simple circuit which I built
to one of my audio amplifier projects to control speaker output relay. The
purpose of this circuit is to control relay which turns on speaker output
relay in audio amplifier. The idea of circuit is wait around 5 seconds after
power up until speakers are switched to amplifiers
Audio Auto Shutoff - The purpose of this circuit is to automatically turn
off any device plugged into its power outlets after a certain period of time.
Shutoff is activated by an absences of an audio signal or by a standard timer
function. This unit would be connected to speaker terminals of a stereo system,
tape outputs, TV earphone jack or audio outputs etc. Once the audio signal drops
below a predetermined level
Audio Detector Circuit
Audio Graphic Equaliser - Simple 7 band eqalizer
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 two common emitter amplifiers, the first stage has a
preset resistor which may be adjusted for a FSD.
Audio line isolator
Audio Line Isolator #1
Audio Line Isolator #2
Audio notch filer
Audio Peak Reading Meters
Audio test accessory isolates & matches loads - EDN-Design Ideas: This
low-cost, switchable, dual-impedance transformation circuit comprises a single
conventional transformer and two minimum-loss pads.
Audio Test Oscillator - As a piece of test equipment, an audio oscillator
has to be considered essential for anyone working in with hi-fi gear. Together
with an audio millivoltmeter (as described in Project 16), and even better if
you have access to an oscilloscope, you will be able to make proper measurements
on everything from preamps, RIAA equalisation stages (for vinyl disks), tone
controls, crossover networks, etc.
Audio Transformer (app note) - notes on using audio transformers for
balanced signal interfacing
Audio Voice-Over Circuit
Audio VU Meter - LM324, 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
Auto Shut-Off for Cassette Players & Amplifiers
Auto volume control
Automatic Charger for Battery Operated Hi-Fi Preamps
Automatic Loudness Control - Simple add-on module Switchable "Control-flat"
option
Balanced Audio Input Circuit - 109KB PDF file
Balanced Line Driver & Receiver - Use these to eliminate hum for long signal
leads
Bass Beat Extractor - an automatic gain control circuit followed by a low
pass filter, converts beat into a sharp pulse suitable for triggering strobe
or chaser
Bluetooth Headset - Intersil Application Block Diagram
Bridging Adapter for Power Amplifiers
Buffered Headphone Driver/Preamplifier - With a fast Motorola buffer as its
only active circuitry, this design specifies the highest quality parts and
careful construction to avoid signal coloration. The author includes
instructions for substituting other buffer ICs. Designed by Eldon Pawliw
Build These Noise-Canceling Headphones (plus: Binaural Mike Headset, Audio Probe
& Parabolic Mike) - Muzzle the din and relax to the sound of silence with
headphones that combat the uproar with "anti-noise." The author includes
modifications for a binaural microphone headset, an audio probe and a parabolic
microphone. Designed by Jules Ryckebusch |
