Parasound A21 or Odyssey Stratus

Odyssey is noticeably lean.

Almarg............

I use an Audible Illusions Modulus 3B all tube preamp with my Stratos Extreme with zero problems.

Papostol...........

I have a Rogue Cronus Magnum in a second system and I do not find it lean at all. You can swap out the preamp tube (the middle 12au7) with a Mullard CV4003 from Upscale for less than 100.00. There will be no more leanness in your amp. I think it is the Monitor Audio speakers and not the amp. If you feel you must change the amp, I would go with the Odyssey Stratos. It is on the warm side of neutral and is not bright or etched at all.

Get something with tone controls or a sub. It's not always audiophile approved, but you will be happier with the sound.

I'd like to throw a 3rd option into the mix, and that is the Merrill Audio Taranis. Just posted a review of it. Was considering a new power amp myself and the A21 was on that list. Went with the Class D Taranis. 100K input impedance and running it with a tube preamp. Very large amount of power. Does not sound lean. You can home audition the Taranis courtesy of Merrill. Audio Advisor will allow a 30 day trial of the Halo if you wanted to compare the two side by side. Personally, found the 60 pound weight of the A21 a little intimidating. Good luck in your decision.

Cannot speak to Parasound, but I highly commend Odyssey. I had a Stratos Dual Mono for a good many trouble free years, and loved it. (I'd not have said it ran to the lean.)

Odyssey kit is routinely available used, and Klaus is a good guy who cheerfully supports 2nd hand owners.

You could much farther and fare worse.

John