Amps under $5k that are resolving at low volumes?

I would tend to agree with Zd542 about the speaker being the issue. After moving from a private home in the suburbs back into a city apartment I also looked for a system that I could enjoy at lower volumes. What I discovered in my research was that this seems to be more a function of the speaker than the associated system. There are not many speakers that really play well at low volumes.

IMHO the best speaker that I heard at low volume was the Harbeth SHL5. I heard a few others like the Vandersteen Treo and VLR Wood that sounded almost as good at low volume but the Harbeth stood out from the group. I had foolishly sold my Super HL5's years ago but I lived with them for more than 2 years. I ended up with the Vandersteen VLR Wood and though not quite the equal of the Harbeth, it is still a very enjoyable speaker at a much lower price point. YMMV.

I suggest you talk to your Magnepan dealer about your dilemma as he may have suggestions specific to your speaker.

"03-15-15: Robr45
Isn't this more a function of the speakers?"

No. All of the components contribute. Not only that, but you can have a situation where one component can stop all the others from performing to their potential. For example, I have an amp that doesn't image well. When I put it in a system that otherwise has components that excel in imaging, the whole system is brought down to the level of the amp. It makes it sound like all of the components have an imaging problem.

I would concur that the Maggies may be the main factor with the low level resolution.
Having owned 3 different pair, low level detail is not what they are about.
If you are after low level resolution I would recommend full range electrostatics or horns.

Best set-up I ever owned for low volume listening was a Pathos Twin Towers into Vienna Acoustics Mozart's ... a close second was a Cary 300SEI into ProAc 1SC's

Merrill Audio Thor monoblocks