Best digital format (non streaming)

I noted down the referenced sites for hi res downloads. I will visit and check out what they have (and cost). Thanks for posting.

I have compared uncompressed FLAC to the WAV file and I can't hear the difference.

CD is best 

"CD is best": I have a decent (for my level/aspirations) receiver with a DAC. And my CD player has also a built in DAC.

As a first 'try', I would like to compare the CD player analog into receiver vs. CD player digital out (and conversion in the receiver), using (depending on which CD player I uses) digital coax, optical or HDMI (?) to feed into the receiver. 

Is that a practical test? 

I was utterly surprised when I listened to my ripped CD played from my laptop via 25 ft USB C cable via Schiit Modi 3 analog into the receiver, vs CD player into receiver (computer sounde a LOT better). 

The difference was so obvious, that I actaully start to suspecdt that the RECEIVER is treating the analog in different (maybe has some 'sound enhancing' switched on) compared to the digital in from the CD player. I will repeat the test in 2 different ways: 

a) use the CD player ANALOG in the receiver and compare to digital input

b) use CD player ANALOG and compare with Modi 3 analog (again, identical CD and ripped CD).