Suggestions for an amp

Those monitor audio Silver 8 will drop down to pretty low impedance in some areas of the bass/midbass.  If you wanted a different receiver, try to get the biggest heaviest receiver possible.  Maybe used if it's in your price range, like a used Yamaha RX-A3060 or something.  Denon has large receivers as well. 

Ultimately, you might be better getting a dedicated amp with a big power supply to drive those Monitor Audio.  It's going to perform much better than any receiver.  Maybe Emotiva if your budget is low.  Or look into an Odysse Audio amp.

Agreed, that's why I suggested putting in a big amp.  When I suggested Emotiva, I was really thinking of the bigger XPA amps that they have.  That UPA 700 is somewhat weak in the power supply department.

Yeah, the Hegel H160 would be absolutely awesome to drive those Monitor Silver 8.  It does include a pretty good digital DAC, but it does not have a phono input (so you would need a separate phono preamp).

The Parasound Integrated is going to be a warmer amp with not as much high frequency detail/air, but you might want this with those bright Silver 8 tweeters.  However, the Parasound Integrated includes a phono input as well as a bass management crossover system.

The Marantz are nice, but they aren't that big of a power supply (only 70 watts / channel) and they are going to sound warm/slow like the Parasound.

Otherwise, I have a couple of Emotiva XPA-1L 250 watt monoblock amps that I have not put up for sale yet for $650 plus shipping (or $850 loaded with Furutech rhodium fuses).

The Music Fidelity M3si is a fine piece, but it is a little light in the power supply for these specific speakers.  I'm sure it would work fine, but the M5si would be a better choice. 

Both the M5si and Hegel H160 are about in the same price and league.  Music Fidelity is going to be very smooth and refined, but soft, however very smooth and pleasant to listen to.  The Hegel is going to be highly detailed and revealing, more air and resolution.  It depends on what you think you want.  My own personal tastes go towards the detailed/resolution side.

The suggestions for integrated are really if you have separate sources (such as a dedicated DAC and/or turntable).  In that situation, an integrated would do better because of the superior preamp in the integrated.

If you are going to use the Yamaha receiver as the source for all music listening, then an "Integrated" may not really help because the sound is still generated by the Yamaha receiver "DAC" and still goes through the Yamaha "preamp circuits".  If you are doing this, your best bet is to just get an external amp and connect it to the "preamp outputs" of the Yamaha receiver.

With an integrated, you are paying for both a "preamp" and an "amplifier".  A straight dedicated amplifier would be cheaper and allow you to focus on finding a more powerful amp.

The Cambride 850A integrated is a very nice integrated - maybe not quite as nice as Hegel, but a very refined sound.  And not as powerful as Hegel.  But like I said, if you still use the Yamaha receiver as your primary DAC/preamp, I would not bother getting an integrated.

The "Pure Direct" mode in receivers is somewhat more of a marketing thing.  It does bypass all the "processing" stages, which include EQ and crossover/bass management.  However, in the Yamaha receivers I have tested, it actually sound better with Pure Direct turned off.  I think it goes through one more set of preamps and create a fuller/smoother sound.  The "Pure Direct" mode was thin sounding and very sterile / solid-state sounding.  Just my opinion.

Soooooo. if you are going to still use the Yamaha receiver as DAC and preamp for all music listening, then start looking for a nice high current amplifier.   The Parasound A23 is nice, but a little light on brute force and will be on the warm side of neutral with soft high frequency response.  Something like my Emotiva's I mentioned above would be faster and higher resolution, or an Emotiva SA-250 on Audiogon.  Wyred 4 Sound SX500 if you want the clean Class D type sound.

Thoughts?

The Cambridge Audio Azur 840a V2 will likely do better than your Yamaha receiver.

There's a Krell S-300i integrated amp I would look at on usaudiomart for $899   (NOT the KAV-300i one -- that's older).  The Krell makes nice stuff.  The S-300i is 150 watts/channel.  It is likely this is the closest that we can come to the Hegel sound quality / sonic signature.

Cambridge CXA60 is too small for Monitor Silver speakers, in my opinion.  Sort of same with the M3si.

A NOTE: none of these integrateds will have a phono preamp built in, so you will have to get a separate phono preamp for your turntable, unless you already have one.  The only integrated I know of that does include a phono input is the Parasound Integrated, which typically goes for more than the Hegel anyways.

Peachtree Nova 150 is a Class D integrated.  There are two camps with Class D, as some people love it and others do not.  It would be educational to read Erik's latest Class D thread (they are all much the same):

https://forum.audiogon.com/discussions/the-truth-about-modern-class-d

That being said, The Nova will probably be just fine to drive those Silver 8.