Sjöström Audio

http://www.dahlbergaudiodesign.se/del1/del1.htm
Bengt Dahlberg has made an excellent description of how to build a "band"-tweeter. The article is in swedish but you may understand quite much since there are lot's of pictures. You can also send him a email.
http://groundsound.com
Very nice looking surface mounted power amp modules. You can also find a digital crossover filter. He sells kits.
http://www.meier-audio.homepage.t-online.de
This Dr. Jan Meier has a couple of interesting and nice looking designs, a headphone amp with crossfeed and a power amp built with 44 pc. of opamps! Cool!
https://www.electronics-project-design.com
Practical electronics project schematics, parts list, component descriptions, product testing and other references for electronics hobbyist and electronics designer.
http://www.svenskaturistforeningen.se
The swedish tourist society. If you want to see Sweden, this is the site for you. The site is available in english also.
http://www.susan-parker.co.uk/zeus.htm
This woman(!), Susan Parker has designed an very odd amplifier which has no feedback and only two active devices. Very rare, indeed.
http://sjostromaudio.com/pages/index.php/hifi-projects/123-qrv02-headphone-amp
  Click on the picture to get a larger view. I designed this amplifier as a result of reading postings at HeadWize. The forum is I'm afraid closed down. I call it "underkill amp" or "Cmoy deluxe". The performance is outrageous in headphone amp terms...
http://sjostromaudio.com/pages/index.php/hifi-projects/124-qrv03-headphone-amp
This headphone amplifier design is based on a patent by Mark Alexander. It's a patented current feedback design. Design by Per-Anders Sjöström. You may take a look in the application note AN-211 from Analog Devices. Click on the picture to get a larger...