This CD-player is based on the regular 524. The importer of NAD in the Benelux (Belgium, Netherlands and Luxembourg) has upgraded it to the 524 improved. Better and more expansive Op-Amps, better golden Line-Out's and more silver have been added to the player. Also the D/A-converter has been upgraded with better capacitors.
All the improvements have made the player about $200 more expansive but it's worth every penny. The player is only available in the Benelux, so when you drop by, please go to an audio-store and ask to listen to this CD-player, you won't regret it.

I compared the 524i with the Marantz SE-6000. Also a very good player, costs $100 less, so when you won't go over your $500, try this one. Even compared it with the Rotel RCD-971. Quite as good as the 524i (HDCD available!!!), but more expensive, $700.
I also tried cheaper and more expensive Denon's, but none could compete in any way with the NAD, Rotel and Marantz.

Note, if you want a CD-player with a lot of functions, try something else. This machine can only PLAY CD's!!!