Which amp specs really matter?

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Yes, but I read it again and pulled this quote out from Mr Nelson out (below) Seems to apply to this discussion and many others I've seen or been a part of, and also goes back to the quote from the HH Scott guy that said we just might not be measuring the right thing(s):

"Nevertheless, I am trying to make a point that relates strongly to the apparent disconnect between subjective experience and simple measurements of distortion"
 
Having a background in EE, specifications can tell you a lot about the design, layout and construction of a device - if you fully understand what the parameter in question represents and the factors impacting it. Most of the specifications I see today for audio equipment are essentially meaningless. The numbers shown on the spec sheet have NO value unless the test conditions are noted for the parameter. Probably some of the worst equipment designed could achieve an excellent spec for say, IMD with the just the right test conditions. So be wary of specs in general unless there is sufficient detail to support the numbers.

On a personal note, my immediate attention goes to what I equate with the dynamic power of the amp. Output power specs into 2, 4, and 8 ohms. Music with good dynamic range is going to have rapidly changing peaks and valleys. Speaker impedance is going to vary over the frequency span. Does the amp have sufficient reserves to respond to these demands. Secondly, I'm interested in SNR which is the window that dynamic range occupies. A poorly designed amp and poor layout will often be plagued by power supply harmonics that will raise the noise floor and offer additional opportunities for IMD.

As others have suggested though, personal listening will offer the best option for assessment of what you might like. Some folks just love 2nd harmonic distortion, some don't. But trying to find opportunities to audition something WITH your system has gotten cumbersome these days. Some online retailers offer 30 day returns so there are some options - it's just a PITA with a big , heavy amp.

Good luck with your search.
Which specific parameters can be subjectively evaluated? Whether they are manipulated or not by the manufacturer does not render any of them moot. Truth is not cancelled by lies. I concur with the ones you've chosen; are there any more? Which ones are descriptors for bass/treble transient performance, timbre/tonal accuracy, linearity, bottom end weight/top end sustain, low level resolution?
 
As I said earlier, I've kind of gotten over my early adult, 1970s slavish devotion to numbers when it comes to hifi, but given a career as an analytical scientist, I do kind of have to believe that most if not all important parameters can at least in principle be measured. I don't think the "hifi" community has yet figured out what those parameters are (other than the crudest and - not coincidentally - easiest to measure such as harmonic distortion, signal to noise ratio, bandwidth, square wave rise time, frequency dependent phase shift, etc.) or how to measure them.

This being said, I think that Stereophile (i.e., John Atkinson) bless his/their hearts, does a good job of testing amplifiers objectively/quantitatively and (more to the point) does a good job of representing the results with clear and cogent graphics.

If anyone reading this thread has never stooped to reading one, give it a go; how about this one, e.g.?
A fine "audiophile"-grade (for better or worse) amplifier from a gifted designer noted for clever and sometimes iconoclastic designs that produce excellent sound.
https://www.stereophile.com/content/pass-laboratories-int-60-integrated-amplifier

Read Herb Reichert's subjective review prose -- or not -- and take from it what you will... but, more to the point, read John Atkinson's prose and view the data in the Measurements sidebar:
https://www.stereophile.com/content/pass-laboratories-int-60-integrated-amplifier-measurements

-- also read, and consider, Atkinson's summary statements in the Measurements sidebar.
 
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Agree. Now we must rely upon good return policies.

I have at least five audio stores in a reasonable distance from me and I still rely upon good return policies. Why? Because things don't always sound the same in my home in my system as they do at the store.

When I worked at a hifi shop in the 70s, we regularly loaned gear for a weekend eval - following a credit card swipe should the evaluator not return (which never happened in my experience).

How is that different from a good return policy?
 
I have at least five audio stores in a reasonable distance from me and I still rely upon good return policies. Why? Because things don't always sound the same in my home in my system as they do at the store.
Which is why borrowing a component for evaluation in your system is the simplest and best way in my opinion. If you don't like it, you bring it back and your credit card is never charged. Done.

How is that different from a good return policy?
The above scenario avoids the hassle of going through the process of purchasing, tracking the shipment when signature is required, unpacking - while potentially needing to tender an RMA, re-boxing, shipping back and processing refund if you don't like it.

While I've done the latter, I greatly prefer the former.
 
"Nevertheless, I am trying to make a point that relates strongly to the apparent disconnect between subjective experience and simple measurements of distortion"

Nice, Mr. Pass. ;) :)

A sine wave is not music. Make both camps happy.
 
When I acquired my Martin LoganCLSZ2 I tortured many different amps with only Bryston, Krell, and now Benchmark making the cut...high priced tube apps were meh...these speakers truly are microscopes requiring absolute transparency and stability in design...you can look up the specs of each brand and theorize from there.
 
For me it has always been about the music.

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As for the Emotiva A-100 amp... it is a sweet little amp on the cheap.

What's with the form factor?? If they put the face plate on the long side instead of the short side, their amp would fit on every shelf in America.
What gives??

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I nearly bought one last night when I realized it was too deep to fit in my cabinet.
 
Depends on the speakers..mostly with my power hungry ones I look for high current..doubling down wattage going from 8 to 4 ohms, with sensitive speakers I like a good s/n ratio.
 
What's with the form factor?? If they put the face plate on the long side instead of the short side, their amp would fit on every shelf in America.
What gives??

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I nearly bought one last night when I realized it was too deep to fit in my cabinet.

The form factor is the biggest reason I use it. Half width, but deep, assuredly. However my custom walnut cabinet has the depth, at twenty-four inches; its width (48") accommodates 2.5 components across the top shelf with some room to spare, but won't do three (51" for most electronics).

And while the amp doesn't double down, it does 1.5 down so has some headroom. While they won't drive Khorns to their maximum all-out/balls-out speed, they come close enough for my desired levels. Perfect amp for my needs.
 
Which specific parameters can be subjectively evaluated? Whether they are manipulated or not by the manufacturer does not render any of them moot. Truth is not cancelled by lies. I concur with the ones you've chosen; are there any more? Which ones are descriptors for bass/treble transient performance, timbre/tonal accuracy, linearity, bottom end weight/top end sustain, low level resolution?

Given that the thread has devolved into a "mine's better than yours" exchange, I thought I would still respond.
I don't mean to be rude or anything, but I simply don't grasp your point as it relates to my original post. Sorry.
Perhaps I'm just not properly reading for comprehension or something.

Cheers
 
When I acquired my Martin LoganCLSZ2 I tortured many different amps with only Bryston, Krell, and now Benchmark making the cut...high priced tube apps were meh...
I suspect that's simply a matter of proper amplifier matching. It's impedance curve is almost an inverse of my stats across about half the range.
 
There seems to be a lot of naïveté in the modern "audiophile" community vis-a-vis the criticality of the qualities of the load (i.e., the impedance curve of the loudspeaker) as they relate to the capabilities of the amplifier. A lot of black-magic synergy mumbo-jumbo boils down to the amplifier vs. load.

It doesn't help that modern technology has given us myriad choices of difficult-to-drive loudspeakers, either (from my perspective).

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EDIT: Just to be clear, the phase angle curves are at least as important as the impedance curves in terms of how easy or hard to drive a loudspeaker is. Thus, I don't mean to denigrate any of the loudspeakers above per se; just to illustrate that they'll look (or feel, if you will) very different to any given amplifier, when the signal is actual music as opposed to sine waves or pink noise.
 
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Given that the thread has devolved into a "mine's better than yours" exchange, I thought I would still respond.
I don't mean to be rude or anything, but I simply don't grasp your point as it relates to my original post. Sorry.
Perhaps I'm just not properly reading for comprehension or something.

Cheers


Simple: If the manufacturer states something like 0.001% distortion, but doesn't say at what frequency or at what level, its just a meaningless number. Depending on the feedback topology it is "always" ameaningless number.

Or speakers / headphones:
One is specced 5 - 35 KHz
The other speaker 45-19KHz +-3dB

Which would you buy? And why?
 
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