I managed to successfully set up the dac+ dsp board on my 3b+ and run an rew filter which sends the results via toslink to an external dac. Concerning this setup I have three questions:
1) Can I feed the pi and the board with seperate power inputs? I would like to bend away the three GPIO pins on the pi and feed the board with a seperate 5v 3a sbooster power brick. Is this possible and if so, where to solder it to the board?
2) I would like to feed the audio signal of my pre-amplified phono-signal through the DSP. Can I simply connect it to the P4 terminal on the board and can I keep using the same rew filter that is already running on the board?
3) What kind of components concerning the digital signal are on the board? Is it the same quality components as on the Digi+ Pro? I'm a layman and I might have gotten some things wrong but I'm talking about the processing of the digital signal that is sent out through the toslink port. Is it of the same quality, especially with regard to signal timing, as on the Digi+ Pro board?