@PeteB: Tks for your advice. I will do the order, consider IQAudio before that. Actually I have seen your advice for someone else in another thread already that I viewed the spec of IQAudio where I saw it has 3.5mm headphone jack out. In term of price, DAC+ is cheaper but the one pro is similar but I have not seen people talk much about IQAudio. Anyway, signal out from RCA should be enough for me as it is the best way to connect to Denon amp.
@hondagx35: thank you so much for your advice. I have seen the warning from HifiBerry spec but I do not get what it is. You helped me to get it out now.
So I just type in the code at the command line after root logged in?
For the config.txt file, we can change the output sound? Or this is just to add the DAC into the MPD?
@PeteB, @hondagx35: finally I received the DAC+ from HifiBerry. Simply fix it on the RP2 into the GPIO 40 pins easily. Then uncomment the line of dacplus in the config.txt ...wow its sound is great...at least it is great against to its price . Finally thanks you bro for your supports during last time.
I am discovering more by next step for the dsd dac that I am considering the s.ms.l m8 since it is $109.-