Those AVM20's are about 10 years old now, and minor upgrades to DAC's over the years have happened, whether or not those upgrades are audible is up for debate.
I wonder if there is something a miss with your ripped music as even FLAC files have been known to be missing the odd bit here and there. Some of the newer ripping programs verify the rip against the master to ensure there were not any mistakes(a long process), perhaps this is what is causing the sound differential and not the DAC. It is simply that you are hearing the true sound from the cd.
Well I don't know about every single song I have , but I recently ripped a CD with Exact Audio Copy using the most conservative / secure / verified etc.. ripping possible ie: no burst mode etc.. the best possible rip I can get out of EAC. I then played that WAV file via Sonos digital out to the Anthem AVM20 which was doing the decoding of the WAV file. I'm not even talking about a FLAC or MP3 etc.. just the best WAV rip I can get using EAC. Then I played the original WAV from the CD via my BD player.
I can absolutely hear a difference between the two, no question at all. The CD WAV file just sounds better than the RIP WAV file. I'm not going to go into all the details of why / what I find better, just that to my ears, the CD version is the better version by enough of a margin for me to go out and purchase a dedicated high quality external DAC unit to ensure I get the best out of my hard disk based WAV, FLACs, APEs, and whatever else I have.
