Ghasley, I don't think I disagreed with your point, as I stated in my previous post about an older DAC sounding extremely good, and yes, it was 20 years old. I do think it is quite amusing that you say, "built in, for basically no extra charge" and "with a free dac." I just can't see McIntosh saying forget about those parts and labor when determining the price of a product, although it is probably a small percentage compared to the unit's full price.
The DAC in the C50 and C2500 are the same, verified by an email response I received from McIntosh tech support.
D123phy, there were some problems with early C50's, however software upgrades solved the problem. Also, in my brief research, it appears the C2500 is an overall better sounding preamp than the C50.