(29-Aug-2019, 12:19)thumb5 Wrote: Your argument is quite familiar.  However, as I said, the object of the exercise is not to establish some kind of universal truth about whether the amplifiers are technically different or even result in different sound waves coming out of the loudspeakers, but rather to identify which one I prefer listening to.  Whether or not my ears are "lying" to me -- which is a rather meaningless and provocative comment in itself -- is entirely irrelevant to that process: they are the only way I have of hearing anything, and I am not using them as measuring instruments so their "honesty" or lack of it is a moot point.

Incorrect.  Show me one individual here that is not pushing the opposing view of universal truth that the more expensive model sounds better.  We are on opposite sides of the same bridge.

What exactly is "incorrect"? I am the example you're asking for, because I am not claiming that my choice is the universal truth -- far from it, I'm claiming that the idea of universal truth is misguided because it's a matter of personal preference. And I am not "pushing" anything, I'm simply stating my preference and asking for you to stop telling me that I am somehow deluded for having made that choice.

(27-Aug-2019, 04:54)David A Wrote: 2 amps can satisfy the same criterion but one can exceed the other in the extent to which it satisfies that criterion. The fact that both satisfy the criterion doesn't mean that they will perform equally well in satisfying it. Lets say you only need 100 watts/channel into 4 ohms. An amp specified to deliver 140 watts and one that specified to deliver 200 watts both satisfy the criteria but measurement procedures for testing specifications are standardised and a standard test load will be used to confirm the specification. Speakers aren't standard test loads and one amp may be capable of handling the load a given speaker presents better than the other. The amp that handles the given speaker better may be the smaller amp or it may be the larger but whichever one handles the load better will perform better with that speaker. The fact that both meet the specification doesn't mean that both will perform indistinguishably with the same speaker.

I see you point, if you are comparing apples to oranges, Devialet Expert (Pro) to Micromega M-One.  Here, it is apple to apples, Devialet Expert (Pro) to Devialet Expert (Pro) so the criteria are equally satisfied within the limits of the smaller apple.

Quote:I remember seeing somewhere the specs for the power supplies of the different models and there are differences in the size of the power supplies. My understanding is that the 140 can only deliver 50% more power in a dual amp setup because it is current limited, and the 220 only delivers twice the power in a dual setup because it is limited by it's ability to dissipate heat. The 250 can deliver 4 times the power in a dual setup because it suffers from neither of those limitations. The architecture of the power supply in each case may be identical, the capacity of the power supply in each amp is not identical. It is not the case that the 3 amps are identical in every performance respect apart from power output.

All Expert Pro's are using the exact same 4000W power supply and architecture.  The D140 "output" is hardware limited to 210W (30A PEAK) in dual-mono mode, a 50% increase (I suspect to avoid reverse engineering a software hack).  The D220 "output" is software limited to 440W (40A PEAK) in dual-mono mode, a 100% increase (I suspect to lesser heat dissipating efficiencies).  The D250 "output" is not limited at all to 1000W (70A PEAK) in dual-mono mode, a 300% increase.  The only difference between each besides cooling efficiencies is the amount of peak current they supply.  There are no differences to the quality that is supplied.

Quote:As I said, the specifications tell you about what was measured and not everything relevant to the amp's performance gets measured or included in the specification sheet. The specifications tell you nothing about performance parameters that were neither specified or measured. No manufacturer provides specifications for how well an amplifier deals with the non-standard load presented by every speaker, they provide a specification based on a standard load and the only way to find out how it will work with your speakers is to hook them up and listen.

The day when we can dispense with the need to listen and know everything about how a speaker will perform with a given speaker under real life conditions are still a long way away. Until that day people will be reporting differences in sound quality between amps which are capable of delivering enough power for their needs and there are reasons for the differences they hear which have nothing to do with one amp having more or less power output than the other. If there is a difference in power output then there will almost certainly be other differences as well. All other things besides power output are never equal in real life, even with amps in the same range such as the Expert Pro models.

Let's look at this from another point of view.  Why should Devialet make their amplifiers sound different?  Wouldn't that go against the very ideal of what a Devialet should sound like?  Will the real Slim Shady please stand up?  Nowhere will you find Devialet promoting one Expert (Pro) model sounding better than another but they hold no reservations that one Expert (Pro) model will be more powerful than another.  So are you telling me you know better about their product than they do?  What's wrong with building various amplfiers to suit various needs but all sounding the same?  Once again, making BIG power is expensive, but price alone is a very very very poor barometer for sound quality.  I know this for a fact.

(29-Aug-2019, 13:36)RebelMan Wrote: ...
All Expert Pro's are using the exact same 4000W power supply and architecture.
...

May I ask how you established that all Expert Pros have the same power supply (I thought the 140 did not have the same PSU as the other models)?

Back to the topic...having bought a copy of the Será Una Noche album (Todd at MA Recordings was extremely helpful, by the way), I ran ocenaudio's statistics function for the track "Nublado" mentioned in the article I linked to yesterday.  Here's the result:

   

(Sorry that it's come out so huge.  Does anyone know how to make vBulletin display attached images at their actual size rather than ballooning them up like this...?)

If I read that right, we have a crest factor of about 18 dB on one channel (and 14 dB on the other).  Roon gives the album as a whole a DR value of 14.

Now, the thing is, casually listening to this track I'd have guessed it was very undemanding on the amplifier.  It's basically rather sparse, tango-style music played exclusively on acoustic instruments -- about as different as it could be from the Pan Sonic track in the video at the top of the thread!  But, confirming what the article says, it requires a lot more amplifier headroom than you'd expect to reproduce the peaks without error.  Since it's generally quite sparse, it's easy to turn this up to the point where it doesn't sound overly loud yet you could be running out of headroom on the peaks.

Incidentally it sounds like a very nice album, from what I've heard so far.