Hand Clap Electronic Control:  turn relay on and off by hand Clap (added 4/02)

Headbanger Amplifier:  (schematic added 10/06)

Headbanger Headphone Amp:  (circuit / schematic design added 6/06)

Headphone Amplifier (circuitdb):  Both halves of the circuit are identical. Both inputs have a dc path to ground via the input 47k control which should be a dual log type potentiometer. The balance control is a single 47k linear potentiometer, which at center adjustment prevents even attenuation to both left and right input signals. If the balance control is moved towards the left side, the left input track has less resistance than the right track and the left channel is reduced more than the right side and vice versa..... (added 02/07)

Headphone Amplifier (connact):  (circuit / schematic design added 6/06)

Headphone Amplifier (headphone):  An amplifier to drive low to medium impedance headphones built using discrete components. (added 6/06)

Headphone Amplifier (redcircuits):  (circuit / schematic design added 6/06)

Headphone Driving Circuit for Soundcards:  (electronic schematic added 8/02)

Headphone Monitor Amp:  (circuit / schematic design added 6/06)

Hifi Headphone Amplifier:  (circuit / schematic design added 6/06)

High Quality Intercom:  (diagram added 6/03)

High Quality Intercom:  (electronic design added 10/06)

High Resolution Volume Unit Meter Simplifies CD Recording:  06/21/01 EDN-Design Ideas / (added 5/03) Digitally recorded music on CDs offers superior quality to that recorded on vinyl records or tape, but most prerecorded CDs have an annoying characteristic: The average volume levels of the recorded signal can vary by as much as 14 dB from disk to disk. Significant variances, such as 4 dB, can occur from track to track on a single CD. This variation can be a problem when recording your own CDs because you can end up with large variations in loudness between songs....

Home Theater Receiver:  Intersil Application Block Diagram  (app note added 6/06)

Infrared Cordless Headphone:  (electronic Circuit / Schematic added 10/04)

Infrared Head Phones:  Using this low-cost project one can reproduce audio from TV without disturbing others. It does not use any wire connection between TV and headphones. In place of a pair of wires, it uses invisible infrared light to transmit audio signals from TV to headphones. Without using any lens, a range of up to 6 metres is possible. Range can be extended .....  (added 7/03)

Infrared Theremin Musical Instrument:  (electronic Circuit diagram added 03/03)

Kumisa Mk. Ii Headphone Amp:  DIY headph1-amplifier project using AD844 and some special transistors (added 4/02)

Light Organ for Car:  flashes3 low voltage Light, operates at10-25-Volt voltage, in PDF format, text in Finnish (added 4/02)

Line level signal to microphone input adapter:  (diagram added 2/07)

Linkwitz Cosine Burst Generator:  part of speaker measurement set described in the construction article (added 4/02)

LM358 preamp:  (schematic diagram added 2/07)

Load Sensing Automatic Switch:  apply power to the entire audio system by turning on1-item, simple circuit (added 4/02)

Loudspeaker Protection and Muting:  (circuit diagram added 1/07)

Low Distortion Headphone Amplifier:  (electronic circuit added 10/06)

Low Frequency Sinewave Generator:  (electronic circuit added 2/07)

Low Noise Balanced Microphone Preamp:  (diagram added 1/07)

Low Noise Microphone Preamplifier:  (diagram added 2/07)

Low Power Op-Amp - Audio Amp (Intercom):  (electronic schematic added 1/07)

Magnetic Cartridge Amplifier:  (electronic circuit added 7/03)

Making Differential Probes:  For sensing audio signal voltages across devices that are not ground referenced (added 4/02)

Microphone mixer:  (circuit added 2/07)

Microphone phantom power supply:  (diagram added 2/07)

Midibox 64:  (electronic circuit added 4/05)

MIDITester:  (electronic schematic added 8/02)

Mini-Box 2w Amplifier:  Designed for self-powered 8, 4 & 2 Ohm loudspeakers Bass-boost switch  (added 3/05)

Minimalist Discrete Hi-Fi Preamp:  (electronic circuit added 2/07)

Minimum Theremin Kit Schematic:  (schematic / circuit added 2/07)

MP3 Player:  Intersil Application Block Diagram  (app note added 6/06)

MS Stereo Decoder:  (schematic / circuit added 2/07)

MS Stereo Microphone:  (diagram added 2/07)

Noise Canceling Headphones:  (schematic / circuit added 10/06)

One Transistor Theremin:  (electronic schematic added 8/02)