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.