Sjöström Audio

http://diyAudioProjects.com
DIY Audio site which contains a wide variety of DIY projects which include speakers, amplifiers and preamplifiers (chip, tube, solid state) and cables. You can also find a forum.
http://www.ampslab.com
"Lot's of kits here, such as power amps and even the famous and patented Alexander amp.You can also download a better copy here http://www.sjostromaudio.com/hifi_files/misc/AN211_better_text.pdf"
http://www.klaus-boening.de
This german guy is dedicated to tube amps and vinyl. He has also designed a very interesting balanced RIAA phono amp and also a turntable.
https://www.amb.org/ti/audio/analog-b.html
Mr. Ti Kan has made a very nice turntable. Please notice that the website has frames.
http://waltjung.org/PDFs/WTnT_Op_Amp_Audio_1.pdf
This circiut is called diamond buffer or Jung super buffer (because of this article in the subject). The buffer can be used after an opamp with or without feedback, altough feedback is recommended. Part 1.
http://waltjung.org/PDFs/WTnT_Op_Amp_Audio_2.pdf
This circiut is called diamond buffer or Jung super buffer (because of this article in the subject). The buffer can be used after an opamp with or without feedback, altough feedback is recommended. Part 2.
http://www.customanalogue.com/diytubegainclone/index.htm
The original "Tube Gainclone for DIY Buffs" website by Joe Rasmussen. Inverted GC with Tube Buffer and interesting features, such as LPF to shape bandwidth and tweak sound character (better soundstaging), zero feedback above 200KHz. Extensive spectral...
http://winsome-labs.com
Tripath amplifier available kit or assembled. 45 W per channel Tripath amplifier, quality build with small size. Sold in bot h kit and assembled form.
http://tangentsoft.net/audio/
DIY headphone amps, META42 and PPA called. One of the best designs for the DIY community. Very nice looking pcb's for sale. The amp is similar to my SMD QRV-04.
http://leachlegacy.ece.gatech.edu/lowtim/
Professor W. Marshall Jr. Leach have designed a very interesting power amp with high slew rate.
http://sjostromaudio.com/pages/index.php/hifi-projects/130-qrv09-headphone-amp
Click on the picture to see a larger view of the pcb. The performance is outrageous in headphone amp terms. See the technical data! Interesting features: The pcb fits virtually any single opamp Room for good coupling caps (if you must or like)...
https://www.hifiberry.com
HifiBerry has various DIY stuff usch as DAC's preamps, RIAA amps, power amps, power supplies etc.