Recommend a power amp to pair with Yamaha A-S1100

The power amp would need to be "gain matched" to the gain of the S1100, unless you would be using an active adjustable crossover.

I'm way behind the times on active crossovers (used tube based ones in the 80's) but I would expect that a current high quality SS active stereo crossover would start @ about $1K and perhaps 3X that for a tube based one.

Never had much luck/gain (pun intended) with passive bi-amping, which is what I'm guessing that you are considering, and active bi-amping gets expensive and more complex.

You have highly rated/thought of gear (amp/speakers) and a HUGE listening room.

Do you have the speakers on the 4 ohm taps?

Seems like that should be OK, but if if not then perhaps consider a couple of powered subs to gibe the amp a break.

DeKay

The power amp would need to be "gain matched" to the gain of the S1100, unless you would be using an active adjustable crossover.

That’s true, or you can use the Yamaha as a pre-amp only and look for an power-amp powerful enough to drive your speakers.

A used Sunfire signature 600 should has no problem to drive the Monitor Audio PL300 II in your 17x38 room.

http://stereotimes.com/amp010500.shtml

Well, you spent serious $$$ on the speakers — not so much on the integrated. Not saying the Yammy’s not a nice amp, but driving a $15k pair of speakers with a $2500 integrated is, IMHO, a bit of a mismatch. Not only are your speakers likely underpowered, as you’ve seemingly already determined, but you’re also using the preamp section of the integrated that by necessity had to be designed to meet that relatively low price point, which to my mind isn’t in the league of doing full justice to your excellent speakers either. Point is, despite adding another amp you’ll still be performance limited to some extent by the preamp section of the Yamaha. Or, put another way, it’s a continuing bottleneck to better overall system performance. (If there’s one thing I’ve learned about building an audio system, it’s to NEVER underestimate the importance of the preamp.)  Plus, as DeKay alluded to, you’re potentially opening a can of worms by bi-amping with two different amps.

So, if I was in your situation I’d sell the Yamaha and use that plus the funds you were going to drop on another amp and buy a better used integrated that will both up your power and likely give you a better preamp section as well. One potential option would be a Hegel H360, which is a $6000 integrated, and there’s a nice one available now on US AudioMart for $3500 (or you could get an H300 for under $2000). I think your PL300s would significantly appreciate and reward you for upgrading to an amp of that caliber.

Sorry if this seems a little forward or harsh as that’s not my intent at all. I just think your speakers could give you a lot more of what they’re capable of if you feed them with even better upstream electronics. Best of luck in whatever you decide.

At this point - after spending serious $ on speakers and the integrated amp - I’m hoping for a decent yet significantly more budget friendly power amp. New or used. I’m talking $500-$2000 (hard stop). The power amp can be upgraded in a couple of years.

Well, focus on one thing at a time is a good upgrade path, at least financially...

Thanks for all the advice so far, much appreciated. I really do like the Yamaha, so maybe stepping up to something like the A-S3000 might be an option.

ill add in another question here while I’m at it: I have the Blusound Node 2i. I got it b/c of the MQA capability. What would be a step up in terms of a streamer/DAC? Ideally I’d like to have the ability to play MQA (whether that means two separate components or not).