Good Suggestions for Tube Amps under 6k

Thanks, everyone, for very good suggestions.  I'll be looking at each of those.  Yes, the LTA Ultralinear + gets a lot of support.  It was also suggested by Lou of Daedalus and others.  Before finalizing anything up ahead, I just wanted to see what others might weigh in on it.  I do want to say that the Primaluna is a very fine unit. It's given me some wonderful evenings over about a year.  I cant' help but think that there's just a bit more of it that I could gain in an upgrade. 

Again, thank you to all for your thoughtful suggestions!   All the best.

I bought an Aric Audio Transcend Push Pull a few months ago and I’ve been delighted with it. Pure class A, triode or UL, variable gain and feedback using quality pots. You can run KT150, KT120, KT88, or El34 interchangeably, with varying power output, of course. I prefer KT150. Auto bias. Dead quiet. Sounds rich, dynamic, detailed, linear. For reference, I run several systems, two of which are SET-based (high quality 2a3 and 300b amps). This is probably the best sounding push pull amp I’ve used, and I owned a VAC 300.1a for six years, and also have a Manley Stingray II, which is El84 PP. With the upgraded Jupiter caps and a few other extras, it came in at $5k flat. A serious bargain. Aric is a genuine pleasure to work with and he really cares.

I ask again, what improvements/sound characteristics are you looking for over and above what the PrimaLuna is giving you?

+1 Charles Dad line magnetic 805

or 845. 

I would go for Atma Sphere MP-3 preamplifier + Atma Sphere M-60 tube amps. MP-3 is also the best preamplifier you can have for your money and probably the best value for $$$ in audiophile world. If you need more power or you want to save some USD, you can replace M-60 with Atma Sphere Class D. Deadalus speakers usualy have 8 or 6 ohms and, more importantly, a flat impendence curb. In this situation OTL amplifier such Atma Sphere M-60 shall work just fine, and will provide you all benefits of the tube technology without any disadvantage. Speaking in general, tube amps are happy with high efficiency / high impendance speakers. A good tube preamp such MP-3 will sound (much) better than almost any solid state preamp. Keep in mind that preamp is the "conductor" of the system.