ICs with great natural sounding highs?

Acoustic Zen Matrix Ref II
Straight Wire Crenscendo

Cardas Golden Reference is very good in this area but some will say its too slow. I agree with Rodman99999 about the Kimber Select 1130. The Kimber Select series are all wonderful and priced to suit anyones needs.

Anticables and other non-shielded IC designs sound best to my ears in the HF.

ET

If you have a chanced to try Purist Audio 20th Anniversary Aqueous XLRs, I think you would like these a lot. They sound excellent. I had Cardas Golden Reference, AZ Silver Ref II and Matrix Ref II.
PAD Aqueous XLR is a better interconnect. Much more natural sounding and non-fatiguing. I use Purist Aqueous speaker cables as well. I think these cables sound most natural, at least to me in my system.

AZ Silver Ref II is a nice cable but it has artificial flavor to it that I didn't appreciate. Matrix Ref II is definitely a great cable for the money, especially used, but it has its limitations. Compared to more expensive and neutral cables, it is a bit grainy in the mids and also has the AZ house sound, with sort of plasticy sounding highs at times. Not 100% natural. You mostly don't notice it until you try another cable that sounds neutral. I had Silver Ref II/Matrix Ref II XLRs combo and substituted it with Purist Aqueous XLRs and sold the AZs shortly after. Very good cables, but they are not as natural and real sounding as the PAD Aqueous is.

I would also suggest Synergistic Designer Ref active XLRs. They have the qualities you are looking for. But the Purist is my favorite XLR so far. Although, same cables may have different qualities in different systems. So you need to try in your own system to determine what works for you.

I think that the Analysis Plus Solo Crytal Oval ICs are more evenly balanced than the Cardas GR, having stronger lows and slightly more dynamics, while still maintaining the smooth highs that Cardas does so well.

Dave