After my expierences with several players for the raspberry PI I finished my best player.
First I started just for fun with an diy dac with PCM1793 directly connected to the I2S port…worked very well. Now I was curious what is possible in terms of sound quality. First choice for the dac was PCM1794. This is my favourite dac at the moment, better than many newer and higher bit dac’s. Followed by an I/V stage with LME49720 and LME49710 output stage.
For internal decoupling and best sound quality there are 3 power supplies, seperate for the PI included hf filter and on/off circuit, one for the dac and the analog output stage.
The most difficult and even very important part is the I2S signal from the PI to the dac, it should be terminated on both sides. Best result I had with coaxial RG174 cable.
For the music data I’m using an external SSD harddisk.
I’m very satisfied with the result.