Current projects:
P. Millett's Sound Card Interface
Long term projects
Measurement:
I'm a DIYer, and that means for me a lot of test equipment. I bought a lot of Heathkit gear in my day and still have most of it, supplemented with a Hewlett Packard oscilloscope and Tektronix audio distortion test set, but the Heathkit gear is still my mainstay.
Since an Audio Precision test set seems to be forever out of my reach, I'm taking a crack at a sound card based analyzer, as above.
Amplifiers:
My main amplifier is based on Marshall Leach's design, version 4.4, with a massive power supply (about 1/4 farad!) on a dual mono chassis. I've been building his amplifiers since the late 70's with excellent success, to the point that I've neglected making a serious effort to build anything else.
At the moment I'm considering Jan Didden's design using Hawksford error correction...