100W, 200W, or 300W?

May I follow up on @almarg advice above and suggest you hold on to your new speakers which are excellent.
Amp: consider an ATC S(?) 150 integrated. It retails far below the Macs and, all things considered, it sounded excellent driving the model up from your speakers (804).
The driving power and clarity and subjective feeling of control were top-notch.
ATC is known for their speakers -- and I love their top 2-way and their 3-way models, but I was hardly expecting them to turn out so capable electronics... a totally unfounded bias as it turned out!

My room is a little smaller than yours: about 15x15x10 high. Sub is eventually on the TODO list to fill in the bottom end - but after amp and streamer upgrades.

@eisenb11 If your room really is these dimensions then I don’t think you’re going to need all that much power since your room isn’t that big. If you are not overloading your old harmon kardon then this is all the proof of that you need. But you do have a different problem- your room is square!

It is very difficult to get the bass to work properly in a square room! The most elegant solution is to employ a Distributed Bass Array and to correct minor problems, add room treatment. Standing waves are a huge problem in a square room, and room treatment won’t fix it on its own. You’ll need to break up the standing waves (otherwise you’ll have one-note bass with the rest of the bass almost non-existant).


If this were my system I would be looking at this issue first, rather than looking at increasing amplifier power! You need that amplifier power to make bass notes without distortion, but if they are being canceled out by standing waves in your room, no amount of power will fix that- because the more energy you put into the bass is irrelevant if it simply cancels itself.

The best distributed bass array system I’ve seen is known as the Swarm and is made by Audiokinesis in Texas. Essentially it is 4 subs, each about a 1 foot square by 2 feet high. You place them directly against the walls. Two are in front, and the other two are asymmetrically placed elsewhere in the room, maybe one to one side and one in the rear; by doing this standing waves are broken up and you get even bass distribution in the room down to 20Hz. They do not operate above 80Hz so you can feed them a mono bass signal (so they can all be fed from the same bass amp) and as long as they do not go above 80Hz then the main speakers will convince you that bass drums and bass guitar is in front of you since their harmonics will be coming from the main speakers.

I am very unconvinced that you need more power. In particular, if you took the bass notes out of the main speakers (some subwoofer crossovers do that) then you’ll find your amp has plenty of power.

@auxinput Being new to this, I'm still figuring things out - but that's why I came into this thread with an open mind - despite wanting a Mac, I'm now seriously considering other options and doing research on the many things that are being written in this thread - learned/learning a ton. After all, what would be the point in me asking for input if I didn't care what you all had to say! Keep the info flowing! :)

@ei001h Yeah, that's what I'm laerning - after listening to the videos, I really liked the detail from the Luxmans. Also, they seemed to tame the tweater without being overly mellow. My concern with the Macs now, if they may be a little bit too laid back for my taste. As you mentioned, I have a highly resolving speaker and I'm looking for something that will pair well with it, without overdoing it and getting me fatigued - currently with work-from-home in full swing - I'm listening to the thing all day!

I'm located in Redondo Beach, which is a suburb of Los Angeles. With COVID in full swing (and beyond) over here, I've been trying to limit going out for the time being.

What do you think of the Levinson integrateds? Haven't done much research into that brand yet, but I know that they've been around since I was a kid.

Did some initial searching for Luxman, but they seem hard to find used, in general. The few that I found appeaer to be Japan imports that need a step-down converter. Is this the norm? Or am I looking in the wrong places to find these?

@atasphere those are the general dimensions of my room, but it's more square-ish because there are things jutting into it like a closet, offset door, entry way, etc. I do have acoustic panels on the way (eventually) from GIK, but they're super backordered. Expect them at the end of the month. I have corner traps up to the ceiling to take care of an open corner. The other corner, can't fit corner traps, so I have a 6" monster trap that will go against the wall near that corner. 6" monster trap on the wall across from the speakers in the center. 6" alpha traps with some diffusion on either side of the wall across from the speakers. And two quadratic diffusors to go between the speakers. Should be interesting!

So I’ve been thinking about this more, and I think @atmasphere has a point - maybe watts really isn’t a big deal for me. After all, I have 100 wpc right now and I can’t crank it, as is, without going deaf. Probably the room acoustics of my small room. 
Assuming that’s the case, is there any advantage of considering a smaller Class A as well? Say a Luxman 590 instead of a 509/505?

I think it’s 100% given at this point that, unless I stumble on a crazy deal that I need to jump on, I really need to wait until I have my acoustic panels up in a few weeks before buying anything - need to see how they affect things as my room is probably magnifying sounds right now (it’s echoey). 
I still haven’t ruled out Macs because they still do sound good and their integrated, unlike Luxman, has a DAC (And upgradeable to boot!) which covers 2 of my wants vs one. I also like that they have more tech on their side as the Mac can be more easily integrated with Roon through USB - that gets me volume control through the Roon interface that I primarily use (when I swap my Sonos for a USB streamer). 
Lots of good info in this thread - you all are awesome. I’m learning a ton and considering paths that I never would have considered.

Keep it coming!

@eisenb11  If you can't clip your existing amp then possibly yes to a class A amplifier. High end is all about nuance!

'Echoey' isn't good- that makes the room more lively and harder to enjoy at higher volumes. So you may find that once the treatment is in place that you need more power. My advice is to sit tight until the room treatment comes in and you've had some time to fiddle with it to see what works. You may find at that point that more power will be useful, as that room treatment will absorb some acoustic power and has the ability to tame harshness in the room; both will cause you to turn the volume up higher.

A mark of a good system is when you can't tell that its playing loud; that it sounds relaxed and effortless, yet if you try to talk to someone right next to you, you find that you have to yell.