This sounds like a magnetic crossfader (ethernal) from Ecler.
So all 4 channel faders on the x1700 are user replaceable, those look like ALPS faders, strange the x1800 does not have this
There seems to be little to no similarities between the x1700 and the x1800. As if another company made them.
I agree 100% the feel of the faders, the meter colors, there are some things the x1800 does have, but it is almost like the 1970 to mid 1980 home stereo components, some had bass and treble some had bass midrange and treble, the new stuff does not offer those features, a little off topic but audio purest will understand. Ok I may be a little biased but my recent use on the 1700 really has me seeking to purchase one. Denon has made certain dj products and audio products, before 2002 that were revolutionary from dj cd decks to dual cassette decks that had pitch control.
Another company did make it.