PS I must add the the C-2000 is already excellent !
Quite as good as the C-2400 and the C-2800.
The real difference relies in the optional cards, extensions : mainly for phono, turntables.
You can add a better Accuphase card (more expensive, of course) as option on the C-2400 and C-2800.
Having a Lamm LP-2 for phono, I didn't mind that and bought the C-2000, a great preamp.