30 June 2008

DIY Class A Headphone Amplifier

The computer sound card just didn't cut it when it came to driving my 32 ohm Grado SR80 headphones, so the need arose for a decent desktop headphone amplifier. Lately I have been reading a lot about Class A amplifiers and have been eager to try one, so a small and simple Class A headamp seemed like a logical first step in this direction.

The circuit is a simple single-ended amplifier with an active load. An inexpensive IRF610 MOSFET is used as the output device and a LM317 voltage regulator is configured as a constant current source (CCS). The power supply is a regulated wall wart which works very well and there is no hum. For the enclosure I used a dead external CD-ROM. This worked out very well as it will reside on my desk at work. I'm sure everyone will be wondering why I have an old external CD-ROM hooked up to a new laptop!

The results were very good. Despite the simplicity of the amplifier circuit it sounds surprisingly good. For more details, photos and a schematic, see the DIY IRF610 MOSFET Class A Headphone Amplifier Project page.

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07 June 2008

DIY Audio Projects Forum and Site Updates

We have updated the DIY Audio Projects webpage. Most of the changes were cosmetic, increasing the page width to 1024px from 800px, adding a Google Custom Search and general clean up. The wider page will allow us to use larger photographs in future projects.

In the past we have had several requests for a message board. We have added a small DIY Audio Projects Message Forum so feel free to register and participate.

The DIY Audio Projects Photo Gallery is growing slowly. If you are looking for inspiration or ideas to build something, take a look at some of the pictures. If you have some DIY Audio photos, do share them on the gallery.