Sjöström Audio

http://sjostromaudio.com/pages/index.php/hifi-projects/126-qrv05-diamond-buffer
  The component side and also solder side. The component print The performance is very good. See the technical data! Interesting features: The pcb fits virtually any SOT23 small signal transistor and almost any SOT223 power...
http://sjostromaudio.com/pages/index.php/hifi-projects/187-dct03-the-dc-trap-high-end-style-heavy-duty
Click on the pictures to get a larger view. Do you have an amplifier with a (sometimes) buzzing toroid transformer? This DC trap or DC filter removes or at least lowers the buzzing. Interesting features: Room for up to 6 x 68000 uF snap-in high...
http://sjostromaudio.com/pages/index.php/hifi-projects/120-qrp01-the-gainclone-high-performance-power-amplifier
Gainclone - The most popular amplifier in the world(?) A LM3886 from National Semiconductor. The heart of a Gainclone. It took a while to understand what "GC" was, or Gainclone. What a name! A couple of IC's (LM3875, LM3876 and LM3886) from National...
http://sjostromaudio.com/pages/index.php/hifi-projects/121-qrp02-the-smd-gainclone-high-performance-mono-power-amplifier
QRP-02 - The first SMD Gainclone amplifier in the world(?) Click on the picture to get a larger view. The world's frist DIY SMD Gainclone Specifications for the new advanced Gainclone. 50 um pcb with groundplane Fast recovery rectifier diodes...
http://sjostromaudio.com/pages/index.php/hifi-projects/139-sps01-sjoestroem-power-supply
Click on the picture to get a larger view. This design is based on Jan Dupont's idea . The goal was to make a huge power supply with high-end rectifiers and as versatile as possible. Interesting features 2-layer pcb with 70 um (2 oz.) copper. 2...
http://sjostromaudio.com/pages/index.php/hifi-projects/111-jsr02-sjoestroem-super-regulator
Click on the pictures to get a larger view. The component side. The pcb is rather small. Some background can be found in my JSR-01 project. This design is based on my JSR-01 project and the goal was to make the pcb smaller than the JSR-01 project...
http://www.railtestnordic.se
Rail Test Nordic is a winter test track high up in nordic wilderness. It goes from Jörn to Arvidjaur which is the winter test area for cars
https://www.ianjohnston.com/index.php/onlineshop
Ian Johnston has designed a extremely good handheld ultra precision voltage source with a low price.
https://www.eevblog.com
This is the hub fo for the EEVBlog, forum, youtube etc. This is a gold mine for all with the interest for the electronics.
https://www.engineered.ch
This firm has really nice looking pcb's with DAC's, clocks, digital filters etc. They also do design work in general.
http://www.digitalaudio.dk
Danish firm which manufactures very high performing DAC's and ADC's. The use ADC chips from Crystal and DAC chips from AKM. The products are for professional use.
http://www.adx.co.nz/products.htm
A 20 years old class D design. I have no idea how good the design is/was. Notice that this is a frame website.
http://www.prototypeaudio.com
AW-diy online shop. Web shop for DIY audio stuff, like regulatirs and clock oscillators.