The third step was to purchase the DAC and class D power amplifier hat to place on top of the Raspberry PI2B . A good choice was X5000 board selling by Suptronics with integrated 192 kHz/24bit high-quality ESS DAC and the Texas Instruments ClassD amplifier (TPA3118) offer up to 2x35w of crystal clear amplification for best sound quality.
Referring to
suptronics.com/miniPCkits/x500