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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
(added 4/02) |
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300 Watt Subwoofer Power Amplifier - (schematic added 9/02) |
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3-Way 12dB/ Octave Crossover - Contributed project, simple 12dB/ Octave crossover
network. (added 05/06/07) |
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48V Phantom Supply - Low noise 48V regulator and phantom mic supply circuits.
(added 05/06/07). |
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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. The
author provides detailed instructions for optimizing the ....Designed by Chester
Simpson (circuit design added 04/05/06) |
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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....(circuit design added 04/05/06) |
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A Reader's Xover - This is well worth reading if you can't decide on biamping
(added 6/07) |
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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 (circuit design added 04/05/06) |
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A-B Switch Box - Can you really hear the difference between amps or cables?
(circuit added 6/07) |
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ABX Comparator - Full ABX testing unit, without microcontrollers or a PC (circuit
added 6/07) |
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Active Subwoofer & Controller - (schematic added 9/02) |
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Add headphones to a Class D Amplifier - 07/09/09 EDN Connect headphones to the
MAX9704 and make a quieter lab or office.....(design idea added 08/09) |
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Add on Stereo Channel Selector - (electronic Circuit / Schematic added 10/04) |
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Amplificateurs audio - en Français (added 08/08/08) |
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Amplifier Phono Input as Line Level Input - (electronic schematic added 8/02) |
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Amplifier Thermal Protection - (schematic added 9/02) |
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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 (circuit design added 04/05/06) |
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AN215: CS4201/CS4202 Headphone Jack Sensing using GPIO - (app note added 6/07) |
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Analog Synth Keyboard Schematic - (electronic circuit added 2/07) |
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Anti-RIAA Equalizer for Line to Mag Phono Converter - AS071 Jenson Transformer
Application Note (app note 6/07) |
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Arc welder sound simulator - (diagram added 2/07) |
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Audio Amp Output Power Limiter - (schematic added 9/02) |
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Audio Amp Timer - Turns-off your amplifier when idle for15 minutes Fed by
amplifier tape-output (added 9/04) |
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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... (added 11/05) |
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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 a
….(added 4/2002) |
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Audio Detector Circuit - (diagram added 2/07) |
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Audio Graphic Equaliser - Simple 7 band eqalizer (diagram added 2/07) |
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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.....(schematic design added 11/02) |
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Audio line isolator - (electronic circuit added 2/07) |
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Audio Line Isolator #1 - (electronic circuit added 1/03) |
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Audio Line Isolator #2 - (electronic schematic added 8/02) |
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Audio notch filer - (electronic circuit added 2/07) |
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Audio Peak Reading Meters - (circuit added 7/02) |
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Audio Signal Source - (diagram added 2/07) |
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Audio test accessory isolates & matches loads - 03/16/06 EDN-Design Ideas: This
low-cost, switchable, dual-impedance transformation circuit comprises a single
conventional transformer and two minimum-loss pads.....(design idea added 10/06)
|
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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.....(circuit / schematic added 2/03) |
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Audio Transformer (app note) - notes on using audio transformers for balanced
signal interfacing (added 4/02) |
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Audio Voice-Over Circuit - (electronic design added 6/07) |
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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 (added
08/08/08) |
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Auto Shut-Off for Cassette Players & Amplifiers - (electronic Circuit / Schematic
added 10/04) |
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Auto volume control - ….(electronic schematic added 08/08) |
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Automatic Charger for Battery Operated Hi-Fi Preamps - (circuit diagram added
2/07) |
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Automatic Loudness Control - Simple add-on module Switchable "Control-flat"
option (added 3/05) |
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Balanced Audio Input Circuit - 109KB PDF file (added 4/02) |
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Balanced Line Driver & Receiver - Use these to eliminate hum for long signal leads
(diagram added 2/07) |
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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
(added 4/02) |
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Bluetooth Headset - Intersil Application Block Diagram (app note added 6/06) |
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Bridging Adapter for Power Amplifiers - (schematic / circuit design added 9/02) |
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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 (circuit design added
04/05/06) |
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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 (circuit design added 04/05/06) |
