Once we finalized the SBC the next important thing was the DAC. Choosing a DAC was not as easy as choosing the SBC, it is very subjective selection process. DAC Sound quality changes between DAC chips and Analog front ends and some are liked by some and some are hated, So we had quite a complex task ahead of us.
We took a non scientific approach of doing listening tests with people from all age groups and backgrounds (audiophile/casual/ipod listeners). We played music from all genres like Rock ,Pop ,Classical, Ilayaraja , AR Rehman etc and got their feed back.
The DACs we tested were
Burr Brown PCM PCM5122 in Slave Mode. (Allo Piano )
PCM5122 Based Master DAC (BOSS Allo)
Low Cost PCM5102a
Asahi Kasei Microdevices AK4490EQ
PCM Dacs were smoother and warmer.
The best sounding PCM DAC was the Allo BOSS.
The Piano and the PCM Module did not sound as good on
Hires and 44.4 FLAC files. For MP3 it sounded good enough.
The BOSS DAC had the warmth and depth we were looking for without compromising on the clarity. It was also non fatiguing.
ESS DAC had the best hi frequency resolution , the highs were very clear
and crisp but was fatiguing after a few songs. The younger listeners hated it
since they were very sensitive to the Highs and thought it sounded too harsh.
We could tame the harshness with the analog filters. The high freq characteristic is something we have seen in other ESS DAC like the SABRE DAC from Youlong. ESS felt like it had some unfiltered HF artifacts.
AK DAC This had the best audio quality but needed I2S input with clock which the RPI3 did not have so we used a XMOS USB to I2S converter to get the I2S. This DAC had the warmth ,clarity and had the best tonal reproduction.
So we decided to go with the Allo BOSS for our Rasa Player and AK4490EQ for our reference player.