Luxman leaves me wanting

I think your cables may be part of the problem as well. I found Luxman gear to be quite sensitive to cable choice, but also easily satisfied with the right choice. In the affordable range, I found that the lowest tier of LUNA cables really brought the Luxmans to full glory. They add density and palpability and increase the analogue-y-ness factor.  As you go up the range, you get improvements, but the base power and interconnects work really well.

Try contacting some DeVore dealers and ask their input on what they like with the Super Nines. The Leben is typically a good match. Also, you may want to consider the CODA integrated amp if you don’t want tubes or the Pass Labs as others have mentioned. I believe Audio Archon carries both the DeVore and CODA.

As a Super Nine owner, I found that using a Puritan Audio "Ultimate" power cord to my Puritan PLC added more fullness to the sound. Perhaps the biggest improvement though came when I switched my speaker cables (from Analysis Plus Silver Apex) to ArgentPur 13AWG. Quite the "whoa" moment!. I also use their interconnects which are also quite good. However, it looks like the only speaker cables available now are the AP16’s. The cables are pure silver, without the harsh sound typically associated with lower quality silver cables.

The DeVores now sound quite "full" even at lower volumes and satisfying.

Good luck.

I’m not a fan of trying to shape the tonality of an amp/speaker combo using DSP/EQ. If there’s a specific room anomaly you’re trying to correct then maybe, but if an amp is lean sounding by nature, then trying to change its characteristics digitally doesn’t make a whole lot of sense to me. (Disclaimer- I’m old).

I’ll throw in another vote for Synthesis amps. I bought a Titan A100 before the holidays and it’s a fantastic amp. Big, bold, dynamic, full bodied, extremely easy to listen to. I can’t see myself thinking about another amp change for days… weeks even;)

So you've got 30 wpc of Class A Luxman super stable current power.  And you don't like it.  It's okay.  Class A is a taste.  Nothing wrong.  I lived in the tube world for years and left it because my tastes changed and I now like super fast dynamic non-lush romantic tube sounds and now I'm a Class A and A/B active speakers and oh yes, I run a Luxman 509X.

Some of the advice given above may suite well.  Some is to be discarded.  I assume you are here because you thought someone might know more than you.  Well, maybe not.  For 8K, I'd go with Manley used 300B pre and Snappers.  And yes, I've owned plenty of Manley, so it's not the "I heard that...".  Have fun with your choice.  Cheers

That 590 has 30 wpc in Class A, and about 65 more in AB, into 8 ohms.

I can't offer much advice, maybe borrow or try some different cables, to start.

I have the Luxman L-590AX, which is the version prior to yours. None of the issues you mention describe my experience, but my speakers, etc, are different.

Good luck