Amplifier Power and sound

It seems like PSAudio, in each new generation of power amplifier, goes for more power. For example, the Stellar M300, to M700 to M1200, each of which features among other things a substantial increase in watts per channel. And in reading the marketing material for each it appears that some of the positive characteristics of each amp is related to the amount of total power available, especially for less efficient speakers. But as the website says, “The over-the-top high power output of the M1200 exists not to match a small handful of power-hungry speakers, but rather, to act as the perfect uncompressed power source for even the smallest, most efficient of speakers on the market.”

As a counterpoint to this, I am familiar with Nelson Pass and his First Watt amplifiers (all solid state) that top out under thirty watts into 8 amps, and alternatively a variety of Tube amps, such as those from Decware, that produce even less output power. From a variety of reviewers at least, both these offerings are rated very highly by a number of reviewers.

As a person whose listening tastes tend to be more jazz, blues and vocals, listened to at less than 75db, what advice does anyone have on the arms race in amplifier power versus simpler circuits and less power?

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This subject just kills me. 1200 watts? In a typical listening room? At less than ear damaging levels?
I have a Pass XA30.5. My room is 18 by 25. I sit nearfield, approx 5 ft from my 100 db/16 ohm spkrs at no more than 75 to 78 db and I know I’m listening at milliwatts. It sounds sublime anywhere in the room.
I also have a Decware 2 watt amp and it gets loud enough to piss off the neighbors without audible distortion.
I listen mostly to jazz, no John Phillips Sousa.
PS---- I also had similar experience with Magnapan .7’s in the same system.


The first watt for any amp is always the best sounding. This is true for A, AB, D, etc… A well designed linear amp tends to sound good through out its power range. If you’re driving it at 95% that of what it can handle though, it might start to sound like crap. Distortion, clipping, and likely shouty sounding. This is one of the causes for an ambiguous or collapsed soundstage during a very dynamic passage.

Class D sadly falls victim to this badly. The first handful of watts can sound REALLY good, but the ratio of “good sounding watts” is much less than with a linear amp. This is one of the main reasons it’s so important for Class D amps to have so much headroom. Is anyone even going to come close to the 1200W in the M1200s? I hope not because they’d likely go def, no matter the speaker’s efficiency. The point of all of this headroom in the 1200s is certainly to allow for that effortless, uncompressed sound. But it’s also to increase the availability of great sounding watts. Those first 20 watts in the M1200s sound substantially better than the first 20 in the S300.

Not sure if this helps, but it was the first thing that came to mind.


I appreciate your insight, and tend to agree. I have Magnepan SMG from the 1980s that have been totally rebuilt to as new condition, and the Caintuck Audio Betsys, and Pure Audio Project Quintet10. They all sound great with lower powered amps as long as they are a quality design, even the Maggies that are not very efficient. It seems like the arms race for more power has more to do with marketing than quality listening.

Thanks, I appreciate your insight. I now have a better understanding of the power race, especially for Class D.

Just curious … Sitting 7~8 ’ away from the speakers, sound level around 85 db, efficient speakers …how may watts is the amp cranking out? Is this a constant number across all amps or do they differ?

It would depend on the sensitivity and efficiency of the speaker not the amp or a constant output in watts across amps using the same speakers.

Frequency response: 45Hz–28kHz, ±3dB. Sensitivity: 91.5dB. Impedance: 8 ohms nominal, 2.9 ohms minimum (at 118Hz).

Is there a way to calculate the approx. watts that the amp would need to output?

The sensitivity is typically measured at 1 watt at 1m.

Odds are the speakers are asking for less than 1 watt most of the time


Many manufacturers seem to be putting together mono amps which are equivalent in construction to a corresponding stereo amp but bridged internally and therefore approximately doubling the power. Brings out impressive numbers and should be fine unless the speaker load drops below 2 ohm.
I use one of those, Perreaux monos which give me 750W/8ohm and 1300W/4ohm, to drive Avalon Eidolons in a smallish room. Compared to the 100W tube amps I I had before the difference is night and day. The resolution and microdynamics, not mentioning macrodymanics, are just so much better. The amps need to tell the speakers who’s the boss.
Think of, say, ECM records. There is a huge amount of subtle information on those records but it’s not easy to dig out. With these amps fed by good power cords and with an upgraded pre->power interconnect many of the ECM records finally make sense. Takes a lot of control to push out all those little details that make the music without having to turn the volume to 11.

If I ever manage to drive my BHK 300’s into clipping & distortion I won’t hear it. I’ll be deaf from the decibel level it took to cause it to happen.


No kidding. I’m just learning what the BHK 250 is capable of coming from the M700. Oh my.

My wife says the music sounds much more real. I agree.

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In January I sold my S300 and bought a Schiit Aegir at 20 WPC. I have Tekton Pendragons which are very efficient speakers so I wanted to try a lower power class A amp. I can honestly say I have no need or desire for a higher power amp. The Aegir sounds so much better to me than the S300, or for that matter, the higher power class AB amps I’ve owned. I don’t think I’ve yet come close to clipping with 20 watts and I’ve been at 90db plus in a 14’x18’ room.
Obviously one drawback to lower power is it limits the speakers you can use, but if you have efficient speakers I’m definitely an advocate of a low power class A amp.
I’m sure the M1200’s sound fantastic and tons of speakers require much more than 20 watts, but 20 great watts can make you awfully happy with the right speakers.

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I owned a First Watt M2. It was bliss … within its limits. In the end as much I loved its purity, it was simply too restrained sounding especially in the bass department for me to be happy with long term. I traded up to a Pass XA30.5. More oomph than the M2 simply because Pass overbuilds the power supply of X class amplifiers like crazy. But, still too polite and a bit loose in the bass department. My experience with Class-A in general is that is the area where low power Class-A stumbles and it’s not a sacrifice I’ve been willing to make. I finally traded up again to a X250.5 and found nirvana with all the bass drive I could wish for. The Pass X series are ‘deep Class-A’ biased before switching to Class-AB and that has all the advantages of Class-A with the punch Class-AB provides when the material calls for it. So while I don’t subscribe to the mega power amp philosophy I have a very specific preference that I think treads the middle ground pretty much as perfectly as possible.

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A great deal depends on the speakers you’re trying to drive. My electrostats really demand lots of power and the ability to drive a changing/difficult load that dips below 2 ohms as frequency increases (very capacitive). Without this amp headroom I would definitely have clipping which is both damaging to speakers and amplifiers alike not to mention leads to hideous amounts of distortion. At lower listening levels that “first watt” concept is also important for lowest distortion (class A up to a watt or a few is best in my estimation). But when the music gets wild/dynamic there’s no substitute for power.

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Oh too true!

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I’m not that much of a fan of really deep bass. I don’t use a sub, for example.
But what I do like very much is well defined, realistic sounding bass. I like to hear what I heard for 20 years standing next to the bass on stage; I always put myself there no matter what the gig.
The XA25 does that incredibly well. The damping factor is some crazy high number, like 500 and you can hear it and feel it. Very entertaining amp.

@RonP regarding subwoofer use, I was a hold out for the longest time as my full range speakers have a low end extending to 20 Hz at -2 dB. Very high quality tight bass too which I value. So just bought a single SVS SB-3000 and have it set with low pass filter at 35 Hz. It is astonishing how much this little $1k box adds to an already great sounding system. There are those cases where the music doesn’t have lots of low extended bass, but you’re still aware of the ambient effect of having that sub produce stuff below 20 Hz. Never would have believed it until I heard it. Weird, but true at least in my experience.

You hit it on the head regarding class A…as you are experiencing with your X250.5 …your experience that more power in a power amplifier
makes for a better effortless presentation…

Would love to move up to Pass labs but Parasound A21 running the
1st 8 watts in class A then on up to 250watt/ ch and up to 60 amps/
channel gives me a very large strong deep, wide and fluid sounstage.
In an affordable price range for me.