SBRdac | Performance Test of the Squeezebox Receiver™

This project startet because I wanted to know how good the Squeezebox Receiver™ (SBR) really is when tapping into the direct I2S digital output stream. I work daily with electronic design and have in the past developed high-end audio designs for customers. It was the experience learned from those projects I wanted to use.

The idea was to use very good digital-to-analog convertions circuits too see if the performance of the SBR could be as good as a high-end CD-player. This included both sonic and measurement performance. I startet designing a board that has sample rate converter, DAC and opamp output stage. I also made a multible stage power supply - with individual supplies for the important devices. The design also include a high quality analog-to-digital section - so analog inputs can be used - and some digital (spdif + AES) in/outputs.

After many hours of designing I finally completed it - it ended up with over 750 components and using some of the best audio parts currently available. The PCB board itself is very big, 418x210mm with an area for the SBR in the centre. I used 4-layer design since a 2-layer approach ended up too complex.

The board also have the possibility of comparing different analog stages (I/V and buffer circuits) using add-on daughter boards. They can be selected 'on the fly' using high quality relays.

Detailed information about the design can be found HERE

Project Updates:
2009 April: Board has been semi-assembled and SBR sonic performance has been rewiewed with very good results

To Do List:

  • Assemble and test analog and digital inputs/outputs.
  • Design control board for user interface
  • Design/buy nice aluminium box for the boards
  • Make two SBR replacement boards for evaluating 24bit/96kHz USB audio devices: TAS1020B and TE7022L
  • Make analog stage daugther boards to test performance of different circuits and opamps
  • Make SBR mods to see if there are any performance impact