Lol, I thought you *really liked* it, but ultimately preferred the KB? If so, that's quite different from "The DL-S1 wasn't to my taste", which suggests you didn't like it, so which is it, daftee?
Again, as I discussed on the DL-103 thread, it comes down to 'sounding good' versus
optimised, and in that respect there's no doubt that the AU-S1 optimises the sound of the DL-S1 in a way that simply isn't achievable without it.
That said, we're probably talking about that last 5-10% of 'magic', which such optimising brings, but which won't make the sound if the cartridge 'broken' without it.
After all, I used the DL-S1, to great effect, without an AU-S1, resulting in the likes of Macca and Jimbo positively raving about its sound at NEBO, so there's no doubt that the DL-S1 can still sound great without its partnering SUT.
Marco.