aqui http://avforum.no/forum/showthread.php?t=30960 tenemos una comparativa mano a mano pero no entiendo ni papa, tal vez tengamos algún nordico por el foro.

Según dicen en otras paginas se basan en el mismo aparato pero si hay diferencias a nivel constructivo en la sección de audio (convertidores) y además en el firmware.

(The Marantz DV6600 is a variant of the Denon DVD-1920, so it will mimic the 1920's performance to a large extent. IIRC the DV6600 uses Crystal DAC's as opposed to the Denon's Burr-Brown's. Also, the Marantz appears to support DivX playback, whereas Denon only supported it with their European version of the 1920. The remote controls for both are literally identical.
The DV6600 weighs in at a whopping 5.5lbs. So it's a featherweight. Other than DivX and arguably better audio quality, the Marantz is just a Denon 1920 with a different faceplate. And a higher price tag.)

y ahora ala... volvamos al oppo que nos liamos.