osanto wroteI always thought that with DAC +Pro i would get a better sound on my 510,
Hard to say, but in my personal opinion, probably not an improvement over the 510.
osanto wrotewith de DIGI+ i will make sure that I receive a "pure" sound and the DAC of my 510 will make the rest, is that your suggestion?
Yes! The Raspberry Pi is the "engine" for the streaming player. The DIGI+ provides the digital output signal to your receiver. Get the transformer version of the DIGI+ (it is only about $10 more), or use an optical cable. This should be all you need.
osanto wroteFrom what I saw the DIGI+ is only compatible with Pi 2 there is any solution to Pi3?
I do not know, because I have the Pi 2, but you can ask that question in the Pi 3 thread.
osanto wroteAbout the power supply, any recommendation? you are talking about linear power supplies?
For the DIGI+, you do NOT need an analog supply, because the digital-to-analog conversion is all done in the 510. Just any good supply, the kind of 2A ~ 2.5A supply sold separately, with a connector for a USB cable, not the kind with the attached cable, and not the one usually included in a kit with the Pi. It should only cost around $10, plus $2~3 for the cable.
For the DAC+ Pro, it is more complicated. HiFiBerry has an option for a separate analog supply, in addition to the conventional supply for the Pi. In general, you get good performance with the wall-wart supply, better performance with an analog supply, and best performance with a secondary analog supply. This is just FYI, as I said, you really do not need the DAC, just the DIGI, since you are going through the 510 anyway.
The DAC+ PRO is really intended more for people like me, who want to connect directly to an analog "line-in"/RCA input of a less expensive amp or receiver. (I like my old analog gear, and want to keep using it... at this point, it is free to me... I already own more than one). You have a more modern and more capable digital A/V receiver, and a very good one at that, so, you don't need a DAC+, unless you just want to play with analog circuits...
