Amplifier upgrade advice under $2000


Hi!  I have a new pair of speakers on order and want to upgrade my power amplifier to be ready when they arrive.  My current system is Klipsch Heresy III, Onkyo M504 amp, MiniDSP SHD preamp/streamer/room correction, and SVS SB12 sub.

Scheduled to arrive in December are Ohm Walsh 2000.  Research indicates these like a lot of power.  If the Ohms don’t work out I’ll shop for a used B&W 804, so still probably needs good power.

So, with a budget under $2000, wondering if I can get something that sounds significantly better than the Onkyo.  Used is fine.  Brands I have seen come up in the price range are Classe (ca-150), Vincent (331MK), Krell, PS Audio, Parasound, Bryston, etc.

I want to know if this would be a significant upgrade in this price range.  My sense is that brands like Rotel, Adcom, Emotiva, etc. would probably not change the sound all that much.  I also have a Crown ps-400, for example, that sounds pretty much identical to the Onkyo.

I recently tried out a Rogue Atlas Magnum tube amp.  It sounded great with the Heresys, a definite upgrade. Unfortunately  it created a loud speaker hum that I was unable to fix.  But it did make me crave the tube sound.  But it seems like finding a high powered tube amp to work with the Ohm Walsh is going to be challenging.

Sorry for the rambling, basically, is it worth spending $1-2K on a new amp or should I wait until I can get into a higher price range before ditching the Onkyo (which has those awesome green meters!).  Thanks!
judsondickie
Thanks for all the suggestions so far. I have alot of research to do. The preamp is actually new, I bought mainly for the Dirac room correction ability, which seems very helpful in my not-well-set up living room.  So i'm concentrated on just power amps for now. 

The video from Millercarbon was interesting, a little above my knowledge.  

I like the hybrid power amp idea.  Van Alstine seems really interesting, not sure if those come up used too often.  Vincent looks interesting, I just can't find too much about them online.
OP (Quote) "or should I wait until I can get into a higher price range"
is a very good plan. These threads usually devolve into 50 responses with 100 different amps suggested. The Reality is that the jump in quality from a 2k new amp to a 4-6K new product is significant. (Ignoring used prices) After about 6k, the improvements, IMO, become more subtle and nuanced. Without knowing the specific improved sound you are seeking it would be just a fanboy reply for me to suggest one. Are you looking for more speed? Firm Bass control, smooth vs detailed? What is lacking now? Watts are not going to be the end all solution. Throwing money at an undefined problem is a great way to spend more money. Buying something used until you get the exact amp you want (A path I followed) is not a bad idea at all either. I narrowed my choices down to 2, then saved and waited. The right amp will make those speakers sing so save your hard earned money and get the one you will love. (And definitely spend some coin treating the room.) Good Luck!

Why buy used? The Van Alstine amps are within the budget that you mentioned in your post!
The Parasound Halo int. as suggested above is a great amp with everything you need in one piece was Stereophile A rated.
@yogiboy , is there a particular Van Alstine you recommend?  I got immediately intrigued by the 400R hybrid ($2699) but see there are some nice ones below $2K.  

@phcollie  In terms of what I'm looking for I might not be fully equipped with the audiophile knowledge to say.  I also don't have the Ohm Walsh 2000's yet to know if there are issues.  With previous speakers I've had (Heresy III, B&W dm2, Dynaudio Evoke 30) they each had pluses and minuses.  The hi-end on the Dynaudio sounded fantastic, really silky and sparkly, especially on female vocals.  The Heresy is not as smooth but has a bigger soundstage and gives more of that live concert feel.  None of these (with this amp) have been able to do rock or heavy metal very well.  I listen to alot of 90's and Nirvana, Smashing Pumpkins, and Metallica have all sounded muddled and lacking seperation in the midrange.  So maybe that's an issue with the Onkyo amp.  I listen to a bit of everything so hoping to find an all-around good system.

Hard to say what i'm expecting in this price range.  I have heard some way more expensive Magico and B&W 800 based systems that just made everything sound incredible.