Sjöström Audio
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.
Very nice looking surface mounted power amp modules. You can also find a digital crossover filter. He sells kits.
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!
Practical electronics project schematics, parts list, component descriptions, product testing and other references for electronics hobbyist and electronics designer.
The swedish tourist society. If you want to see Sweden, this is the site for you. The site is available in english also.
This woman(!), Susan Parker has designed an very odd amplifier which has no feedback and only two active devices. Very rare, indeed.
  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...
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...