Schematics / Audio
iPod Super Dock Project
Here is a multi part project from endgadget that shows you how to make a versatile docking station for your iPod. It's a multi part project that takes you through the whole process so be ready!...
S/PDIF Digital to Analogue Converter
S/PDIF is an acronym for Sony /Philips Digital Interface (or Sony /Philips Digital Interconnect Format). The full specification for the S/PDIF interface consists of hardware and software, but only the hardware side will be discussed here...
Wireless Microphone or "Bug"
Schematic and parts list for a wireless microphone...
Audio Analyzer
You’ve just spent a large sum of money for that new stereo and it’s time to fine tune your listening environment with the graphic equalizer. But wait. How can you do that objectively...
Stereo Compressor 
Ever have to turn up the volume to hear dialog while watching a movie and then get your ears blasted by an explosion of sound effects. This stereo compressor circuit from Poptronix addresses the problem nicely. And, since it's from Poptronix, a circuit board layout is included....
Active Subwoofer
Determine the feasibility of incorporating low-cost accelerometers and a feedback loop into subwoofer speaker design to achieve a 10% reduction in total harmonic distortion....
Headphone Amplifier from SDS Labs
This little headphone amp from Sheldon Stokes uses a push-pull Class A MOSFET output stage, being driven by an op-amp. The output stage is included in the op-amp feedback loop, so the distortion figures are amazingly low. The power supply uses a 25 watt torroid transformer, and two adjustable regulators. It sounds very good; surprisingly un-solid state. Included with the PDF file are the schematics and the PWB layout drawings....