audioXpress is the only do-it-yourself audio magazine currently published in the USA. I’ve been a subscriber since the late 1970s and have a nice collection of back issues.
Their web site has plenty of free info so check it out… better yet, subscribe today and support DiY!
http://www.audioxpress.com/
An example of a recent project is the Hybrid Valve MOSFET SE Amp by Stephen Moore, published in the Oct and Nov 2007 issues. They are online for free download:
http://www.audioxpress.com/magsdirx/ax/addenda/media/moore2355.pdf
http://www.audioxpress.com/magsdirx/ax/addenda/media/moore2844.pdf
I got the Dec. issue in the mail today and it had nice surprise in the plastic wrap with the magazine… a cd-rom with loads of free programs! Some are demo versions but the majority are full versions of nice audio related programs and utilities.