100W, 200W, or 300W?

I suggest you listen to the 805 with the latest Krell integrated, K300i sounds amazing

My recommendation for your foray into high(er) end audio: Go listen to a pair of similar sized Focal, Dynaudio, or even Harbeth, and pair it with a Luxman SS integrated. This will keep you satisfied, and sound a hell of a lot better, IMHO.

To be blunt, but not rude, the listening fatigue factor of B&W speakers, matched with the homogenized sound of Mac amplification, will find you back on a forum again in no time. Many of your audio peers, myself included, have gone down the path you are on regarding these two over-marketed and hyped products. In regards to Mac, I was always able to sell my gear easily and for a fair price. B&W-good luck!

Hi OP,

I bought a brand spanking new Mac integrated a long time ago because I had always wanted those blue meters. Turned out it was entirely not the sound I really desired not fit with the speakers I found out I liked.

Better to find a dealer who will let you listen to as many different amps as possible. They might let you home audition older, used gear, which will give some sense of what the latest and greatest from a manufacturer may sound like.

Thanks for listening,

Dsper

@mrklas Thanks! I was able to cross off more boxes by going with separates, so I changed my plan a little bit. I didn't know about the MC152 which basically got me what I wanted without having to go as big as the MC302.

I've been having a lot of fun. Replaced my speakers, then the amp with that new one. Afterwards, my acoustic treatment finally came in so I put that up. Last week, finally got around to making a new convolution filter with REW for my new amp+acoustic updates and loaded that into Roon. Incredible difference from where I started!

The Sonos Connect which I'm using for streamer and DAC is now the weak point in my system. Time to weigh some options for when my wallet recovers a bit...

Congrats!  And buying something not on the list sounds like you were able to identify additional options.

The meters are a bit like fire - hypnotic!

Hi all, latest update:

The amp I ended up buying was... none on my list! I bought a McIntosh MC152. 150W/Ch w 2 dB headroom so no power concerns and also has the autoformers. Nice and laid back, seems to have tamed my tweeters a bit. Only had a chance to play around with them a couple of hours. Those meters are really fun to watch - better than staring at the wall while the song is playing.

Wasn’t in a big hurry to pick something, but a deal dropped in my lap that was way too good to pass up.

@eisenb11

I recently purchase Sonus Faber Sonetto Vs.  I really like them and they are a significant upgrade from my Sonus Faber Venere 3.0s

Digging through the Mac specs it appears that their own direct coupled design has 5 times the damping factor of the autoformer design. While it seems debatable if damping factor beyond 250 has real-world gain, these values seem to be within the “it might matter” range since they’re within the 0-250 range.

@eisenb11 It might interest you to know that no speaker made needs more than 20:1 damping factor and many sound better with less! So more damping factor, if that is the only metric, totally does not matter. Damping factor looks better on paper than it sounds in real life- again, given that such is the only metric. Distortion is far more important, both the distortion that an amp makes and also that which it does not. In general with most amps these days higher distortion is often a sign of lower ordered harmonics to which the ear is relatively insensitive. OTHO very low distortion might only be higher ordered harmonics and the ear is keenly sensitive to those and interprets them as brightness and harshness.

I just looked at the MA5300, I think you are making a wise choice. I don’t know anything about digital beyond CD’s, so I have no idea what it doesn’t have, but the MA352 appealed to me when I saw it’s a tube/ss hybrid, remote control, still has blue meters for you, additional power, (for the future, I agree with you, 100 watts are enough)

I don’t know the price of either one. Buy a used one? McIntosh comes with 3 year warranty, is it transferable? In any case, they are essentially bullet proof, so if you find a good deal on one you can return, or, one you can buy an extended warranty, i.e. square trade, I would go for that.

You didn’t mention, but both of these have MM Phono Input, you will get there some day!

I didn’t see a remote control for MA5300 (many OEM’s forget to show or mention them), MA352 has one, I would want remote volume, and remote balance to improve imaging of CD’s and LP’s, some of which are not quite spot on. A very slight balance adjustment can make a surprising difference.

My office, I went Vintage: some nice 2 way bookshelf speakers from B&W, and a self powered Velodyne sub, a Carver Cube Amp, Reel to Reel, TT, and my computer sound for YouTube, Pandora, CD, DVD, ... Monitor dead center, wonderful imaging, audio or audio/video. I control inputs, volume, balance via my Chase Remote Line Controller, RLC-1, I would never live without one, that solves any amp/preamp with no remote control.

and have set myself up with a perfect equilateral triangle listening spot, wow, terrific. I had to rebuild my office bookcases and desk to make that happen, so glad I did.

Adjustable Crossover, external or built in the sub like mine is, removes low bass before the bookshelf speakers, so they don’t try to make bass they cannot do without distortion and poor volume levels. That helps them shine. Sub just to add a bit, not too much, not aware of it unless I turn it off. Same thing with the sub in the home theater, primarily there for Jurassic Park Dinosaur Stomp.

So... after tons of continued research, I think I’m honing in on a game plan.


First, to address my power concern: 100W is fine. Doing the math, 2m listening distance, at 88.4 dB (measured on stereophile) sensitivity, with a desired volume of 102 dB (loud! I’m not actually going to go near this high) needs 92W. At 100 dB target, drops that to 58W. And that’s not counting amplifier headroom so I think I’m ok with any choice.

I expect the room treatment to have a drastic impact on sound, but I don’t expect it to change the math behind the power needs. That’s because I suspect my room is echoing and magnifying the sound currently which is why I play at lower volumes. Once treated, I suspect that the volume dial is going to go up (which aligns to what others have said in this thread) because I’ll lose the freebie (but poor quality) amplification from the room so that’s what it’ll take to hit the same volume level. That’s why the calculations above are important - that’s direct volume so those are worst case numbers. The volume knob only goes down from there.

I think I’m going to go the organic route and grow into this - as mentioned I’m new to this, so need to temper what I do with whatever little level of restraint that I have. As I just bought a new house and with the economic uncertainty of the zombie apocalypse in play it would probably be prudent to exercise at least some semblance of restraint on my part! Ha ha

That said, I’m heavily leaning towards the MA5300 route right now. Still considering Luxman, but I think the value proposition may be higher on the Mac side (for me).

What’s attracting me to Mac are a few things: they look nice (glass w blue meters!), 1.8 dB headroom leaves plenty of power, the high resale value makes it easier to do the organic jump if an upgrade comes later, and the value proposition - the MA gets me a new amp, has a pre, and also comes with the DA1 which is a decent DAC. Throw in $1k later, and I can jump to the DA2 DAC. I also like the Roon ready capability since I’ve drunk the Roon Kool-aid.

The next thing I had to work out was autoformer vs no autoformer and that discussion seems to lead to a holy war on the forums. Both have their merits, but after listening to a ton of videos and doing a lot more research it appears to be a wash to me... it’s just preference... one choice is not inherently better than the other. My take on it is that it seems to give a more tube like presentation at the cost of bass control and possible some accuracy - I think that’s why the Luxman videos were really shining on me. Digging through the Mac specs it appears that their own direct coupled design has 5 times the damping factor of the autoformer design. While it seems debatable if damping factor beyond 250 has real-world gain, these values seem to be within the “it might matter” range since they’re within the 0-250 range. No single amp design is perfect - you need to make your trades.

That said, that’s why the MA5300 is looking interesting to me. It has the wattage needed for my small room (it’s my home office), has all the toys so I upgrade everything at once, has some growth potential, Roon ready, looks nice, good resale if I change my mind or want to upgrade, and because it’s directly coupled should have performance closer to the Luxman side of the house sonically.

I’m not sure if it’ll sound as nice as a Luxman, but I need to see where things land when I make my trades. The 509 and 507 are really nice! In the end, I don’t think I want to deal with the high power consumption (heat!) of class A, so the 590 is out.

If my room was larger, my sitting distance would increase and that would change everything. During my research, I found the math for dB reduction as a factor of distance and it’s very significant. Just my 2m distance comes at a cost of around 6 dB! That’s huge!

One other factor that I’ve taken into consideration is that my speakers also don’t have crazy bass as they’re 2-ways and they’re size limited. The frequency response bottoms out at 42 Hz. All of the sub options I’m looking at for future growth have built-in class D amps so they’re not affected by what I choose here.

So I guess my saving grace is that my home office isn’t very big! :)

Any ways, just thought I’d share my thoughts so far!

@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.

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!

@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!

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.

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!

Something to note. A huge amount of speakers are 88 Db. Krell or some other amplifier manufacturers make the wattage ratings on some amps seem overstated -or are Krell et al understated I cant remember. The power supply is an important feature to consider when driving difficult loads. I’m with Erik Squires 1 step at a time. Try getting your maximum benefits with what you have now by using room treatment speaker position in relation to walls and your hot seat. Let your Ears be the judge. Calculations only take you some of the way. As for the Blue meters its an aesthetic choice which may be at odds with the sound you are after.

One can always take the stance that ’too much is Never enough....'

A pair of Crown PA amps, capable of running a kilowatt a side...

Into a floor to ceiling line arrays, anchored into both....

’Dropping the needle’ might break the windows, but Hey...

Nothing exceeds like excess...;)

You need to decide what type of sound you're after. You chose a highly resolving speaker and I assume you want an accurate representation without being overly romantic (highs rolled off). Luxman will give you that. Mac will also sound beautiful and will make anything sound pleasing to your ear. B&W with a diamond tweeter will need to be restrained and either Mac and Luxman will do. However, Mac will do it to a much higher degree. 

Also, I recommend you stay away from lesser known, smaller and obscure amp manufacturers. It is true, the more obscure highly specialized amps could give you something special, but at the same time they're harder to maintain and may become unfixable if the dealer loses support or if manufacturer goes out of business. That is one reason Mac retains its value throughout time. They are extremely reliable, and easily serviced. Luxman has a similar reputation. 

Where are you located? What brands do the dealers carry near you? By the way, you can always negotiate the price on a new amp. I usually get at least 15% off. You can do much much better on used equipment. 

@auxinput wish there was someplace to do a real-life side-by-side. I have to admit that at least in the various Youtube and Instagram videos that the Luxman seems to pair with the 805D3s better than the Macs do... 

But, at least for me, online video is good to compare overall themes - but useless in understanding what the sound is really like.

For example, last night I watched a video of my speakers paired to a Mac playing a song that I've played often - and it sounded terrible. But that song sounds much better with my "meh" amp on the same speakers - Hence the nature of beast with online videos - a recording of questionable quality (the video) of the playing of another recording (the subject of the video) ultimately being played on a device of likely even lower quality (my iPad)... :)

You started this discussion indicating you really wanted McIntosh.  That's fine, but keep in mind that McIntosh has a mild and laid back midrange type of sound.  Very pleasing to listen to on a high resolution speaker like B&W D3, but it's not going to be as exciting and dynamic as other amps.

The Luxman that I heard is definitely not laid back.  It is more of the fast high resolution and dynamic type of sound.  Luxman would not be a good pairing with speakers such as Focal or Wilson.  It can come across as being too thing/bright, but they should do very well on B&W.

I suppose it depends on what kind of sound you are after.

Don't rule out either the L-507uXII.  Another top contender would be the Aesthetix Mimas, which would again tame the B&Ws.

@ei001h @twoleftears Ok... I take it back! After checking out of those videos I have to say... dang, Luxman sounds smooth on the 805D3!

It appears that those Luxmans are almost 50% more cost than the Mac gear that I’m looking at.

I believe the MA7200 is around $7k, and the L-509X is around $10k new. I’m having a hard time finding price data on used stuff, but it looks like a used L-509X may be in the price vicinity a little shy of a new MA7200?

I recommend You 1000 W to break easy old bide, tub, sinks....

@ei001h Thanks, I’ll check out that Instagram!

If you wanna hear B&W with Luxman, go to instagram and follow Audiovenue, lots of amps paired to your speakers, listen with headphones. It should give you some idea. 

Luxman is definitely not bright. Very smooth sophisticated amplification. 

Hey there, 
I have the MC7300 I'm trying to trade for the narrow version or just unload. 

But, have to say, I don't listen to my music any louder. But...I hear way more bass and it seems more well-rounded. 

Like my buddy who owns a dodge hellcat. I asked him why he would need 500+ horsepower than you can't use it to its full potential on american roads. He explained its nice knowing if he wanted to, he could. 

I feel the same about having the MC7300

Add Vacuum Tube Audio amps from Tubes4hifi to your research list.  Several options that are top notch at a decent price, and great customer service.    http://www.tubes4hifi.com/bob.htm

OP do not let the cult of McIntosh blind you to the hifi universe. There are a ton of amps that are good matches for B&W speakers that are just as good/better for less money than the comparable McIntosh amps... Ayre, Pass and CODA just to name a few manufacturers, even Bryston I would say. The reason to go with McIntosh is resale value, as the cult seems to have deep roots. As a fellow B&W owner (804 D3s), one thing I will agree with is the need for some power, but less measured in watts and more so measured in CURRENT. Another important consideration if you go SS is how much the amp is biased into Class A. Think about a Parasound JC5 or CODA No. 8 at around 100 amperes and the 1st 18 watts into Class A, or a Pass 250.8x with even greater Class A envelope. Just my 2 cents.

I've listened to B&W speakers a few times and I always come away feeling they are too bright and edgy in the treble region. That said, Luxman would be a good choice for amplification as they tend to be smoooooth.

Where did you get the idea that Luxman is bright?  Current B&W are a little in your face, so something like Luxman to temper them a little would be ideal.  L-507uXII or ideally L-509X.

Thanks all,

Learning a lot here and using your info to do follow-on research. For sure, no decision until acoustic panels arrive and go up (end of the July, early Aug?) then we’ll see where things go from there. Budget isn’t unlimited which would probably rule out some of the more exotic options (Pass labs, for example).

My initial thought is that the B&Ws are on the brighter side of things. While I’m very happy with them, I want to make sure that I don’t choose gear that makes them brighter. I want to do as much as possible with hardware (speakers, amp, treatment) before leaning on DSP for the final round of tweaks and corrections.

@auxinput thanks for that info! Sounds like too much power isn’t an issue and neither would be the bass from your experience - since most of the external subs that I’ve looked at seem to have their own class D power source... so the amp I’m looking for now is just to drive the 2 speakers. And in a room of this size - there is probably only so much power one could take before their ear drums implode.

@ei001h I’ve read very favorable things about the Luxmans. My main concern is how well will they pair with my speakers? B&W is already on the bright side of the things and it seems from reading (and videos) that the Luxmans are also a bit on the bright side - that’s one of my reasons for considering Mac. The Macs with the transformers seems to be a bit more laid back and more forward in the mid range which seems to align with a good strategy to handle the speakers. As you own both Luxman and Mac what would be your thoughts on that?

Tubes are an area where I’d like to play around in the future - a few paths for that if I went the Mac route - for example, get a 7200, then later there is the option to run a tube pre into it and bypass the built-in one essentially turning it into a 200 wpc amp. Or with the 302, obviously, you could just get different preamps for it without having to swap out the amp stage. Both options have nice growth paths.

I listen to almost all music (rock, jazz, classical, r&b, pop, rap, electronic, musicals... very little country though), but the bulk of my listening these days is focused on rock, pop, and vocal jazz. Lots of stuff from the 60s-80s right now, although it’s still fun to spin up some NiN from the 90s - forget his stuff after that! ;-)

@mrklas Curious, what speakers are you running with those?
Thanks

Interesting dilemma as I considered the MC 7200,MC 89000 and MC 302. 
My starting point was a NAD C 375 BEE and ultimately I went with the MC302. 
I believe more power provides more control for the speaker so I wouldn’t fear overkill. 
Your decision is more about value per dollar and for that I’d suggest you consider going with an integrated amp if your current head unit cannot do that. I have McIntosh C 2600 pre amp and MC 302 - it’s awesome and there are numerous combos at the investment level that are excellent as well. 
The 7200 has a DAC that is a step ip from your Sonus and the 100 watt difference from the 302 is not easily heard. 
As an aside, sound delivery from my system is delivered smoothly and listening sessions often are hours I duration because I don’t get any fatigue. 

If you go with Mac skip the 5300 and go for 7200. It should be more than sufficient for your speakers. Ma7200 is a complete package, an excellent DAC and pre amp all in one unit. You'll also save on cables with an integrated. Don't make your life complicated with separates. 

However, I'd advise you to forget the Mac entirely and go for Luxman L-509X. Much better amp in all respects than Mac.You'll have to add a DAC, or get a nice streamer with a DAC ( aurender or lumin). 

 I say this and I own a two Mac amps, preamp, and av processor. I think your speakers deserve a better amp. I was also initially entranced by the blue meters and mid century modern look and bought all Mac equipment. They're not bad at all, very lush, powerful and warm sounding. But once I heard what other amps could do with my speakers, I could no longer live with Macs. I agree with auxinput, Mac is very laid back and mild.

You know what would sound even better? A tube amp. Once you hear a quality tube amp, you'll never forget that sound. I believe that's where the real audiophilia begins. What type of music do you listen to? 

The more power you have the better your ability to drive worse speakers.  It is better to have always more power and not use it, rather than needing more power and not having it.

@auxinput curious, what amps were those? What are you using now with your 805D3s?

The 250 watt monoblocks were Emotiva XPA-1L.
The 500 watt monoblocks were Emotiva XPA-1

Currently, I’m using Emotiva XPR-1 monoblocks (1000 watt) for my front stage (left/center/right/sub). They have all been completely rebuilt / upgraded. Neotech OCC copper for all internal wiring. 24 x 10,000uf Mundorf caps for main power supply. Nichicon FG/KW for all amp boards. Upgraded WIMA film caps and KEMET film-on-foil caps for all amp boards.   Furutech fuses.

Obviously I’m not anywhere using the full 1000 watts. If I crank it with a heavy bass effects movie, I can get the sub amp to about 70% (which is about 1200 watts into 4 ohm subwoofer load). But the other amps never get above 30% or so with the extreme peaks. The XPR amps have LED lighting on the front that shows how much power it’s generating (like the dials on McIntosh amps).

hi the amp power no more then 150 watt amp for the b w 805d3 how big is the room what is a good spl level for you  if you like the way the speakers sound take the time to match the amp to the speakers it is the only way so they sound nice to you preamp is more of the sound then the amp the speakers are the sound.50% the room is the sound 50%

Power specification is very vague.  Average music power delivered to speakers (dissipated heat) is very low, unless one listens to sinewaves (then it is 50%).  When music sounds about half as loud as the music peak it is 10% of the peak power, not to mention gaps in music or soft parts.  I would speculate it is only a few percent of the peak power - more for heavy orchestral pieces and less for Jazz trio.   Perhaps 100W amp can deliver as much of the peak power as 200W amp, but is specified at 100W only because of the, for instance,  smaller heatsinks.   Both might sound the same with some types of music, like mentioned Jazz trio.  According to FTC power should be measured as sinewave RMS voltage at specified frequency range and rated THD, over specified impedance for period of 5 minutes, when amplifier was preheated at 1/8 of rated power with 1kHz signal for one hour.  It would imply that amplifier rated 200W has to supply this power for only 5 minutes and after that can overheat.  Does it make a sense to test an amp at full power at 20kHz? This will never happen in real life.
I don't often see power specified as FTC power, so power specification can be very flexible (often much worse).  I found in the specification of Icepower module continuous power (40W) and FTC rated power for 0-3kHz (150W).
So we have continuous, FTC and momentary powers and anything in-between.   Perhaps for linear power supply amps weight can be a better specification than power? 

As for the listening distance - Benchmark claims that in average room distance doesn't play role.  6dB loss for double distance applies to open space only.  

Rule 13: In a home environment, the SPL at the listening position is about the same as the 1m response of the speaker in an anechoic chamber.

If a speaker has a measured output of 90 dB SPL at 1 meter when fed with one watt, you can expect about 90 dB SPL at your listening position when driving your speaker with one watt. Room reflections supplement the output of the speakers and compensate for the fact that you are more than 1 meter from your speakers. If you are outdoors, this rule does not apply. But, in a typical home listening room, the rule works reasonably well for a quick approximation.

 

sgreg is correct, speaker sensitivity is not the most important spec when it comes to judging an amplifier and its power output. Also provided you dont clip your amps (especially if they are S.S.) you can never have too much power. In my experience, higher powered amps either S.S. or tube, sometimes dont sound as good as their lower powered brethren. 

Thanks all:

In general it sounds like there is no significant danger by going big (just don’t crank the dial) - I’m more concerned with having enough headroom. Given the size of my room and the sitting distance, I have a feeling that I’ll blow my ear drums out or have the police visit before I blow the speakers.

@chilli42 Based on what I’m seeing Pass looks to be a bit more than I’d like to be spending right now!

@fbgbill thanks! I’ll likely take you up on that PM offer later on as I gather more info!

@twoleftears No one is pushing me in that direction, but it’s the combination of aesthetics and quality - I do understand that I can do better for the dollars but there’s always a trade to be done. The B&Ws fall in the same boat - can do better for the dollars - but they’re still really nice speakers and I really really like the way they look. Don’t want all looks and no bite, likewise, not after all bite and no looks - aiming for a sweet spot in the trade-offs! :)

@almarg that’s assuming you crank the dial, then you’ll likely blow the thing. I’m more interested in head room. Even if we assume that the speaker will blow after 120W, I’m concerned the 5300 will start to sound bad way before that because it’s pushed to the max. To use a car analogy, I’d rather be in a car with a 120 MPH top speed going 60 MPH than a car that’s rated for 60 MPH going 60 MPH... did it in high school, you’d think the thing was going to fall apart on the highway!

@avanti1960 yeah, I’m leaning towards the 7200/302 for those reasons. There is a case to be made for the 302 in that I can play around with different pre-amps afterwards to upgrade without having to change out everything. In the immediate term, I don’t even need a pre-amp... I can pipe my streamer directly into the amp.

@auxinput curious, what amps were those? What are you using now with your 805D3s?

@ditusa Yeah, that makes sense - with more distance, you’re going to need more DB. What would you recommend as a power range given the 805D3 specs? I’m currently giving it 100 wpc using a nothing-special amp (the Harman) and while it sounds really good, it feels like the speakers can be sounding much better. Don’t know how to verbalize it, but it feels like there is more to be had out of these speakers.

hi they recommend 50-120 watt amp@8 ohms that means thy don't have a power rating sensitivity 88Db @ 2' not 8' 8' will be about 82 Db if it had a power rating say 100 watts@ 8 ohms then your power amp should be 3Db higher will 200 watts @8 ohms remember the 805d-3 are good to 96Db spl and thd will be high

Sensitivity Can be way over rated. I have 86 dB Vandersteen’s being driven by 40 watts of class a power. They will play loud enough to to shake the neighbors walls. Bottom line is watts per channel can become the main focus but you also have to consider the other aspects of the amp. If I had listened to all the threads I read on my amp and that it needed minimum 92 sensitivity I would have never bought the vandy’s. Everyone that has heard my system is more than satisfied if not impressed. I am very happy I rolled the dice and just went with my gut.

Get the biggest best amps you can.
300W RMS, or larger.
 You need the headroom, said,many times, when crescendos, drum, or guitar solos, or the song ending slam at the end does happen, you will need the headroom.

I would agree with this statement.  I also have the B&W 805 D3 (previously had D2).  I tested two amps side-by-side with these speakers.  One set were 250 watt monoblocks and the second set was 500 watt monoblocks.  The were the same product line from the same exact manufacturer.  The 250 watt amps were nice, but if you listened closely, the smaller 250 watt did not have quite as much authority with bass (not quite as full bass and not quite as much slam).  It was almost splitting hairs, but the difference was there.  I think a 50-100 watt amp would sound even weaker (but it would still work). 

You don't buy big amps for the total power.  You buy them because they have huge power supply capacitance and transformers.  You will get a lot more punch, slam and midrange/midbass body.  The smaller amps with smaller transformers and capacitance just will not have the authority, EVEN AT LOWER VOLUMES.

The McIntosh sound is more of a mild and laid back signature.  If you say the autoformers create the McIntosh sound, it could be that the autoformers are responsible for the mild/laid-back sound.  Just a thought.  Not arguing against McIntosh.  It's entirely a personal preference.

Just food for thought.

100 watts per channel could be enough but not that particular Mac. It sounds strained at higher volumes compared to other more robust 100 WPC amps.
200 WPC should be enough, I have heard that combination and it sounds excellent, the Mac takes the edge off the diamond tweeter nicely.
the 300 WPC amp would not be overkill but for your listening distance it will be more of a luxury / icing on an already very nice cake.
As a lesson more power is not completely about more volume. It is about sound quality and life-like dynamics and speed at lower volume too.  Think very good bass and attack at low levels.  The amp makes this happen.  
Some people like the jump factor dynamics in high efficiency speakers - you can get this with lower efficiency and higher power.
While the 7200 will be very nice, my ultimate recommendation would be a Mac tube preamp paired with their 200 WPC power amp. Boosts the spend but sounds like you have it, this would make your system golden.

P.S: Note also that the MA5300 has a specified dynamic headroom of 1.8 db. Which means that on the peaks of typical "unclipped programme" being played at high volume the amp should be able to provide approximately 150 watts, not just 100 watts.

In other words about 25% more power than the speaker is rated to be able to handle, even on a short-term basis. Which seems to me to be a reasonable margin.

Regards,
-- Al

For speakers, I picked up B&W 805D3 tabletops with stands. 88 dbSPL sensitivity, 8 ohm. They recommend 50-120W @ Ohm for the amp power on their site.

... For the MA5300, I’m concerned that there isn’t enough headroom. If I even get close to the 94W peak, it means that I’m pushing the amp to the max, so I’d probably be operating in an area of reduced sonic performance since it’s being stressed.

More significantly, IMO, you would be pushing **the speakers** to near the max. Note that B&W’s recommendation for amplifier power, stated fully, is:

50W - 120W into 8Ω on unclipped programme

Meaning that its ability to handle **continuous** power (which is how the amplifiers are rated) is certainly much less than 120 watts, at least if the speaker is to provide reasonably undistorted sonics. Which also seems consistent with the fact that it is a small (28 pound) two-way speaker having a 6.5 inch woofer.

Finally, there are undoubtedly a great many design differences contributing to sonic differences between the three McIntosh amplifiers you are considering. I would not let your decision be dominated by the presence or absence of autoformers, or by any small handful of design characteristics. I would start by researching what amplifiers others use with the same or similar speakers, and what speakers others use with these particular amplifiers.

Good luck. Regards,
-- Al

Most of the time, amplifiers are only using a fraction of the output that they're rated for.  Take the case of amps richly biased into class A: often they never leave A to slide into AB.  Up to a point, some increased headroom is good--think V8 over a straight 6.  The 302 is overkill: horses for courses.  BTW, B&W and Mac are often sold in the same store; is Mac what the store is pushing you towards, because you can do better for your $$?