Which Would You Choose?

Upgrade your speakers, keep the amp and upgrade cabling. 

Another proposing upgrades instead of studying and experimenting and learning what to do ...😉

It is like most people in this hobby know nothing save buying ...

Dont change your amplifier now save if you feel it is not synergetical at all ...

OP listen first  to someone who know about speakers :

• Your room (erik_squires)

@soix and @jeffreyw already recommended what I was going to say. I believe your best bang-for-buck upgrade may be a power conditioner.

Like you, I have a more mostest system. I dropped an AudioQuest Niagara 5000 w/ Tornado power cable into the system, and I was rewarded with better everything. Part of me was expecting no change at all, or a slight change only that wouldn’t justify the price. After that result I had, I picked up some AQ Hurricane power cables and also put a Niagara 1200 on my TV system. I was pleased with the results. I’ve played with a handful of sub 1k power conditioners and some sub 1k power cables and haven’t been impressed with the results. Another power conditioner that seems to be getting ubiquitously good results is Puritan, which is under 2k USD.

I would suggest comparing your Monster conditioner against a standard power strip to start. If you’re not hearing a difference, or if it’s just a slight difference, I bet you'll be pleasantly surprised with a dramatic improvement with a Puritan or Niagara.

And, if your results aren’t dramatic like mine were, then sure, put the money into a different component. I can’t speak to your power amp, but I’d think the NAD could be improved upon. My vote would be to consider the Holo Audio Spring or May DAC/pre’s.

This thread is a great example of people either not reading or reading but not caring and provide their input even if it's ridiculous and not helpful. I'd sooner ask my deaf neighbor for his opinion than some of you people. 

It seems that if in fairness to those seeking an opinion, those rendering an opinion should give the basis for the opinion. If you believe a component is "midfield" whatever that is, you are certainly entitled to your opinion. Obviously, if you have no significant experience, actually listening to that component, that affects the credibility of the opinion. I don't have the ability to judge equipment that I've never heard but perhaps others do