can a new amp amp tame my speakers?

There are enough amplifier manufactures that offer trial periods some simply for the cost of shipping.

I experienced similar issues with my first experience with entry level speakers at more realistic volumes powered by lower wattage linear solid state amplifiers.

I purchased a very newly released PS Audio HCA-2 switching amplifier, my first class D and, since then, three other sets of switching amplifiers including my current Hypex nC400s which power the monitors in my studio. One of the benefits of most of the class D amps that I've audition and owned is their ability to remain sonically stable and uncongested at their higher output limits.

All my A/B and most of the class A linear solid state amplifiers I've auditioned have difficulty in this area, some worse than others. To class D detractors this ability subjectively comes across as cold, sterile, or too forward. The Hypex and a few other newer design switching amplifiers are improving this trait by priority design and not with tubes or with the usual solid state tuning methods.

Even so I can't caution enough the importance of and in home audition if you're switching to a class D amplifier. Personally, I listen to Carver tube amps in my main system. The Hypex are used for track playback of mic locating for which they are ruthlessly accurate.

I loved my Yamaha R1000 and my neighbors Yamaha CFX grand Piano is absolutly stunning. Yamaha's electronics are simply not their strong point and your description mirrors my own experience with them.

That said another amplifier should bring new life to your old speakers. I would suggest learning everything you can about Vandersteen speakers which IMO would be the natural progression from your Kappa's.

A very nice pair of used Rowland Model 6s currently on the Gon would do well with both your Kappas and a pair of Quatro's.

Sorry, I sounded pi$$y there, not my intent. The sub is a ULS15, powered.

Vicdamone - point taken, and I'll admit to a bias against D amps. Unwarranted, I'll grant you, as I have never listened to one, but nonetheless...I'll work on that. The JRDG's look wonderful, but a little out of my price range...;)

I was impressed with a set of Vandersteen's I heard that same day I was listening to the PSB's. Don't remember the model, but they were $6K, about 48" tall, and tapered. Someone was auditioning a Reva 'table, and Peter Gabriel was sounding wonderful!

Sorry, I missed your budget. It's just so easy suggesting higher end gear. Still, those Rowlands would be sweeeet. How about a used Parasound A21?

One point about speakers like Vandersteens, Avalon, and Thiel. Generally speaking they were designed with more emphasis paid to time and phase correctness, and quality crossover design. In my case most speakers that do not do these things well are easily noted and easily dismissed.

I've been looking at Parasound. It 'seems' to my uneducated eyes that the older spec out better than new. Richard Schrma at Parasound recommended a 2250, but the specs on that seem far below the HCA220II for example. I'm trying to get something good sub-$1K, which seems possible but not easy. An A21 seems comparable spec-wise to an HCA2200II, so I've been looking down that path. Nothing available yet...Haven't seen much in used higher power Parasounds, although a non-mk.II HCA2200 just popped up on fleabay. I can't remember the difference, but seem to remember it was a worthwhile difference to the II.

Those Rowlands would be sweet!! Wonder if they'd keep me warm on a cold night sleeping in my car?? :)

That your powered subs didn't seem to help alleviate the high end issues, makes me wonder if the problem isn't just inherent in the speakers themselves. Does the problem occur on all or just some recordings when the volume is raised?