Step-up from Plinius SA-102?

The problem I had with the sa102 was not a lack of power, but sounds like what Inpieces was complaining of. Essentially the sa102 can sound a little lifeless and lacking drive in some (repeat some) systems, despite its considerable power reserves.

It's rare to find Plinius amps not providing enough power, especially the SA-250. In fact, I'm wondering if the amp is really the problem. You must be pressurizing an awfully big room. Maybe you should double check your power situation (also don't run the amps through a current limiting power conditioner.) I guess speaker cables/power cables could also be investigated too for excessive length, proper gauge and/or incompatibility with the amp.

You also may want to "back door" the problem by trying a preamp with a little more gain than your Classe. It's common to overlook the preamp, but a preamp can affect every area rather significantly.

Nevertheless, if it is the amps, you got a handful of good suggestions. I don't think you could go wrong with the super powered Edge, Halcro and Boulder models. On the less expensive side, the Parasound JC1 and McCormack DNA500 may work well for you. However, when you need that much power, considerations such as size, cost and heat frequently become an issue. If so, you may want to try a high powered digital amp (like Spectron) to alleviate those issues. If you like the sound, you could even get 2 of them and still save money.

The SA102 tends to lack bite, and it sounds like that might be why you are hankering for a change. I was in a similar position a few months ago except I was reducing the sheer size of my second system (keeping my lovely wife happy) and replaced the SA102 with a Perreaux Radiance integrated. The music definitely became more engaging, but it did lose some of that muscularity and emphasis on inner textures that the Plinius had. My point is that I doubt that you could say the Radiance was 'better', but I ended up with a more musically engaging system and I am pleased I made the change. If I am right that the music has become a little bland for you, then the issue is probably less about what is better than the Plinius, but simply that the Plinius sound is not what gets your system boogying. There will be many amps that you could look at that will overcome the problem you are having with the Plinius.

Consider a pair of bridged BEL 1001's.
These amps are tough to acquire but have a cult following.
I've heard the Plinius 102's transform to another level when bridged. Why not try this approach first?

I think Duke nailed it, as usual. I have owned Krell before. My favorite was the older KSA 250. I had it for 7 years. The newer ones sound a little sharper to me. Lately I have been listening to the Parasound JC-1's and am very impressed with them. No listening fatigue. These would be over 1000 watt monoblocks on your 83db speakers. I think it would be a great match, try to give them a listen.

The Pass is a good suggestion.Also consider the Edge NL series,Plinius SB300 or Halcros.Lamm M2.1/2,2s?

I agree with Duke and Rsbeck.

Be careful what you wish for. Too much "attack and control" can certainly be fatiguing, as you found out when listening to the Krells. I think the Krell monoblocks are great for a speaker that is difficult to drive, but in a dynamic speaker, it can be too much of a good thing. I had Krell FBP350 MCX's in my system and it was a little too much. I switched to Levinson 436's and for me it was just right. Detail and
accuracy without the fatiguing edge, musical bass without so much boom, just a touch of warmth, wonderful extension, snapped the whole system into place, etc. etc. etc. I encourage you to give them a listen.

Inpieces -

I tried e-mailing you through Audiogon, but I think it bounced.

Anyway, first off that sounds like a fascinating speaker you have there! Sort of a super-Kharma with deeper bass, but low efficiency. That low efficiency makes me think that, if there's one area your speakers could use a little help in, it's dynamic contrast.

The big electrostats I sell, Sound Labs, have a similarly low efficiency (though it's improved a bit of late). So I'm always on the lookout for lively-sounding amplifiers that don't have any grainyness (which the Sound Labs will reveal). An excellent amplifier in this respect is the Parasound JC-1, which is genuine competition for other solid state amps I sell up to twice its price. The JC-1 also works very well on non-electrostats that could use a bit of help with dynamic contrast, such as Maggies. They put out around 1100 watts into the 4-ohm load your speakers present (according to Stereophile's measurements).

There are plenty of JC-1 dealers so chances are there's one within reasonable distance from you who'd be willing to arrange an in-home audition. If you're within several hundred miles of New Orleans and don't have a local dealer, I'd be willing to drive a pair over to your house for you to try.

I'd be happy to take a shot at any questions you might have.

Best of luck in your amplifier search!

Duke

Pass X250 or X350. However, you might want to inquire from someone else if bridging two SA-102s might provide what you are looking for.