NAD M-33 or Hegel H190

I am always hesitant to trade on product for one of similar price. Typically you end up trading one set of strengths and weaknesses for another. At a minimum I would suggest the H390. You are probably correct that the warmer sound of the NAD will be less so and have more detail and imaging with an equivalent Hegel.

It would be a good idea to do some driving, and see if you can listen to one.

As @stuartk pointed out… two sets of speakers is a questionable configuration. This feature is not found on high quality integrated amps. If really great sound is required, typically it will be to one dedicated location. There are switch boxes… although they tend to have a sonic cost.

I honestly don’t think the amp will give you the imaging and sound stage, The speakers will do that. (I believe)
You have other threads about other amp questions so you seem to want a different amp for sure.
The Hegels for what they do are overpriced. Maybe they are superb, and bring out sounds and details you haven’t heard - with expensive cables and speakers, I would love to have one but they are definitely a step up from the NAD.

You can order a Hegel online for 30-60 day trials easily paying for a measly $20 shipping.

If you are to stick with your speakers, my feeling is that the raw power and hardware inside your NAD doesn’t work with your speakers well. It’s not the most musical sound. I would look for synergy, read a lot of reviews. Your budget affords you great choices.

@aldermine

I tend to agree with @grislybutter -- soundstaging and imaging with the H390 don’t disappoint me in my system (keeping in mind that I have stand-mounts) but I’ve yet to read or watch a review of the H390 (and I’ve checked out a lot of them) that lists these factors as particular strengths.

Maybe look here for some ideas?

https://www.stereophile.com/content/recommended-components-2023-edition-integrated-amplifiers-receivers

Are you just tied to the Hegel specifically? Lots of stuff in that price range. I’ve heard the Hegel can be kinda sterile as well so maybe look for something more “robust” sounding. Tubes? Also didn’t say your speakers. 

Curious, have you tried the Dirac Room correction with the M33? If not that’s absolutely the 1st thing I’d do. Room correction in my room makes waaay more a difference than small amplifier differences in my room with my Lyngdorf.