This project is a headphone amplifier based on BUF634 and OPA627. The amplifier operates in class-A.
BUF634 / OPA627 headphone amplifier - [Link]
This project is a Class-A Audio Amplifier based on 2SA1943 and 2SC5200 complimentary transistor pairs. This Super Class-A Amplifier is fully running at a bias of about 1.65A @ 35V, which it resulting in about 58W of continuous dissipation per transistor in the output stage. In this condition, you can highly imagine that the heat sink runs in a hotter temperature, where it can reach approximately 40 Celsius degrees!
Super Class-A Amplifier – [Link]
This project is a homemade speaker. RobertG writes:
It’s a simple speaker, that may be build at home from inexpensive and freely available materials: magnet, cardboard and tape, isolated wire from signal transformer and mini-jack cable from broken headphones.
Homemade speaker - [Link]
DS1802 is a Stereo Digital Volume Control IC. It consists of two 65-position, 45kΩ digital potentiometers with logarithmic resistance properties incrementing 1dB per step. It can be operated under automatic software control via a serial 3-wire interface where wiper settings are written with 8-bit words, or under push button control with simple contact closure.
DS1802 Stereo Digital Volume Control – [Link]
This project is an easy audio amplifier based on 8 pin DIP LM386 integrated circuit.
The potentiometer is the volume control. The heatsink is screwed to an LM7812 12V voltage regulator. There are a couple of caps and a diode on there. The wire with what looks like gum on the end of it is actually the headphones jack wire with a three-pin header molded onto the end using that really cool putty “as seen on TV” that you knead together and it forms really hard parts. I used it to protect the super-thin wires of the headphones jack. The little chip on that board is the LM386. The red- and black-tipped wires coming into the top of the breadboard just left of the diode and the voltage regulator are the leads from a Radio Shack 12V, 500 mA wall wart.
LM386 Easy Amp – [Link]
This project shows how to take a pair of speakers and put them in two of the original iPods where the scroll wheels normally were.
iPod Speaker – [Link]
A Class-D amplifier operates the output transistors as switches instead of as variable resistors, as in more traditional amplifiers. In doing so, nearly all conduction losses in the output power devices are eliminated, leading to a very efficient amplifier. [via]
DIY class-D amplifier – [Link]
If you have ever wanted to plug in a pro-quality microphone and headphone to an iPhone or iPod touch, pay attention and read on. This guide will show you how to make a cable that will allow you to do just that.
iPhone / iPod Touch DIY Microphone – [Link]
Mark Houston writes:
While looking through the local (Jaycar) electronics store catalogue I came across a Magnetic Cartridge Preamp Kit (Cat. No. KC5433). It uses two LM833 Operational Amplifiers (op-amps) and cost $AU39.95. Naturally, the op-amps can be upgraded with higher performance versions.
DIY Moving Magnet Phono Preamplifier Kit - [Link]