As the as the 755 controls a DSP, it will control either one. Like I said, they are the same exact thing, just a different case. The model numbers are different to correspond to the new definition of the letters for that year.
Example:
In 1996 you have the DRX9275L (CD)
and the ARX9270 (cassette)
The D stands for digital, CD
The A stands for Analog, Cassette
The R and X have meanings too, just can't remember them. I found that on clarions web site. I'll have to go back and look for it again.