After a little goggling, I discovered that it's already been done. Over 20 years ago. An ABX comparison was done to see whether listeners could differentiate between music output as a straight, all analog signal and the same music after it had been sent through a loop which contained an analog to digital converter AND a DAC.
detailed account of the test
No discernable differences were found. Granted, both converters were 'state of the art', but that was state of the art 20 years ago. I assume DACs are even better now.
Once mid-fi or better source/pre/pro/amps are in place,I guess the only real place place the place to go looking for bliss is in great speakers, proper setup, and improving the acoustics of the listening room.