@brownsf No, just keep the KRELL it is a great match for the KEF. I love the way that KRELL sounds, and I am normally not a fan of warm smooth sound, but that KRELL DUO really works for me. The #16 is not as smooth or warm and you may not like it as much with the neutral KEF.
I may get a more neutral DAC to add to your system, so you have the Direct Stream and something else to have some variety, especially with the KRELL. I would suggest the Schitt Yggi+ OG but they do not sell it anymore. My too hot on top Benchmark DAC3B is nice on the KRELL (and cheap).
It is all about system matching. My Yamaha NS5000 speaker likely is not a great match with the KRELL. My #16 was not as great with the NS5000 as it is now until I added the Yggi+ OG DAC. Prior to that I found it a bit too warm with the Yggi+ LIM DAC and was thinking I should get another amp. Glad I did not do that.