Try a Benchmark LA4 for a 30-day home trial, I was all in on getting the Makua about 6 years ago. Then looked at the descriptions of both the LA4 and Makua and thought the LA4 maybe a cheaper version of the Makua. I am not even curious about the Makua now.
The Leedh volume control on the Lumin X1 (owned it) was almost as good as the volume on the LA4 preamp. The areas where it was not as good was really not that important in real usage (very low volume).
The Lumin X1 is the only DAC that I think the volume control was similar to a preamp. ALL digital DAC volume controls I owned, except the X1, were lacking to my ears. Just lower the volume and listen.
BTW - I owned the KRELL DUO 175XD and loved it with the LA4 preamp. I was also planning on buying the KEF Blade but did not think it could survive in my home. Another preamp to consider that is similar to the LA4 is the Holo Serene.
BTW2 - Since you were mentioning using a tube preamp in front of the KRELL DUO 300XD. Something I would not do, too warm. I would look at a preamp such as the CODA 07x or Schitt Mjolnir to warm things up. Still too warm for me but I think a better choice than tubes. That Mjolnir is a beauty for $1100. I use it with headphones. Sold the 07x.
