@inna, the best person to offer opinion here would be my very close friend, The Doctor (Mechans), as he’s owned the DA60 and JMlabs loudspeakers at the same time, and brings an incredible wealth of knowledge.
Personally, I feel the larger (4+ output tubes) Jadis amplifiers would represent an ideal match with the JMlabs speakers. Especially, given your insight. My Orchestra Reference offers fixed bias and 2 output tubes per side. As such, lower frequencies are not its strong suit, and that circuit topology presents a more forward presentation, neither of which would complement the Utopias. My DA30, while moving to cathode bias, also doesn’t present the best low frequency performance or control. However, when you move up to the DA60 / DA88S with two more output tubes per side, things really move to the top shelf. You get incredible soulful, rich, full-bodied sound, with the type of lower-end slam and performance that sits as the perfect foundation for the entire musical spectrum.
@daveyf, I’ve been around and own both older and more recent Jadis amplification. My amplifiers illustrate the evolution, though the differences don’t go anywhere as far as some try to tell me. So much of it comes down to output tube selection, as again, my experience has shown tubes more critical to the end result than most other amps I’ve encountered. The company tends to prefer the larger tube types, and have evolved from 6550 to KT90 to KT88 to KT120 to KT150 through the years for reasons related to sonics, reliability / durability, and availability. Personally, I prefer all of them with EL34 output tubes, as I feel the midrange rises to a level that few other products attain.
Regardless of where you head, I hope you enjoy as long and wonderful relationship with your amplifier as I have, and excited to have you as part of the small group of Jadis owners