[rollo]

Two accurate amplifiers both operating under reasonable conditions will sound the same. But there are a whole bunch of qualifications and restrictions that go with that simplification.

  Accurate meaning what in particular ? Thanks.

charles

[Speedskater]

Accurate in frequency response and low distortion.
While amplifiers with euphoric coloration intentionally modify the frequency response or add distortion products.

[RDavidson]

I think you meant euphonic, not euphoric....though I guess maybe some people may find a sense of euphoria when listening. Anyway, to add to the discussion....

I disagree that 2 different amps that measure electrically the same, when connected to the same speaker load (and all else being equal) will sound the same. Electrical performance and sonic performance (the way we humans process sound) are just not 100% correlatable. To believe they are is disingenuous to our complex auditory sensory systems. The only way the amps will sound the same is if they share the same topology and parts. In other words the amps have to be 1:1 the same. This brings me to a related point...

Differences in parts quality can play a MAJOR role in the perceived sonic performance, even though gauges may not find a significant electrical difference. For example, let's say one were to build "twin" amps (same topology and layout). Amp #1 is built with basic, reliable, parts required for the amp to function at 100%. Amp #2 is built with much better quality parts (of the same required electrical values as amp #1). In this example I can virtually guarantee the two amps will not have the same sonic performance. Why would one expect them to? I think it is understood that parts and materials quality matter in any competently built audio component. The "twin" amps should theoretically have identical frequency response and low distortion measurements, however I stand by my statement that they won't share the same exact sonic performance. Here's my point : Gauges and machines can quantify an amp's electrical performance. That's true. But these machines and gauges cannot quantify audible differences that we humans can definitely hear, sense, and/or perceive. With that in mind, I have to question why anyone would place all their bets on data gathered by gauges and machines, without also listening? It makes no sense. It's a half baked judgement call, like drawing a conclusion to a complex book after only reading it half way. This is why the best published reviews of amplifiers offer subjective information (the reviewer's perception of the amp's sonic performance) as well as the objective information (measurements). While some may not be able to relate to the reviewer's experience nor background, this doesn't make the information somehow less valid. If Gordon Ramsay were to tell you that Italian wine tastes amazing, but you've only tasted American beer, is his opinion somehow invalid or less valuable? No. It just means you may not be able to contextualize or relate to his opinion. This is why I always always always recommend folks try things for themselves if at all possible. At minimum they will (hopefully) learn something and build their own experiential knowledge base.

[JLM]

Has anyone done "proper" listening tests comparing amps?  Proper meaning scientifically controlled double blind testing with a panel of trained well qualified listeners, similar to what Toole did at the National (Canadian) Research Council and Harmon International? 

[Letitroll98]

Are we really revisiting the old Julian Hersch trope from Stereo Review days where he claimed all amplifiers that measure the same sound the same?  Really?  Well all those idiots buying Pass Labs and Devailet amps can now dump those mega buck doorstops and replace them with Crown 1500s.  And you don't need to spend large sums of cash to notice the difference, so expectational bias doesn't come into play.  Try comparing NAD, Rotel, and Harmon Kardon amps, all very different sound signatures.

[firedog]

Solid State- Don't think they all sound the same,  but the main factor is if the amp has the power and ability to deliver that to the specific speaker and it's behavior. Once you have that, the differences are small. Decent modern amps pretty much are very low distortion, so that isn't an issue. I think there are many amps that users wouldn't hear the difference in unsighted listening, because the differences are small.

There are differences, but audiophiles tend to do sighted listening and then highly exaggerate the differences they hear, because some of what they perceive is imagined.

And in sighted listening expectation bias ALWAYS comes into play. It's part of being human.

[rollo]

Are we really revisiting the old Julian Hersch trope from Stereo Review days where he claimed all amplifiers that measure the same sound the same?  Really?  Well all those idiots buying Pass Labs and Devailet amps can now dump those mega buck doorstops and replace them with Crown 1500s.  And you don't need to spend large sums of cash to notice the difference, so expectational bias doesn't come into play.  Try comparing NAD, Rotel, and Harmon Kardon amps, all very different sound signatures.

   We can only lead the Horses to the water. Shortly the " Blind Test" will be the next point. Get over it.





charles

[rajacat]

Even "blind" tests have expectation bias.

[Freo-1]

Solid State- Don't think they all sound the same,  but the main factor is if the amp has the power and ability to deliver that to the specific speaker and it's behavior. Once you have that, the differences are small. Decent modern amps pretty much are very low distortion, so that isn't an issue. I think there are many amps that users wouldn't hear the difference in unsighted listening, because the differences are small.

There are differences, but audiophiles tend to do sighted listening and then highly exaggerate the differences they hear, because some of what they perceive is imagined.

And in sighted listening expectation bias ALWAYS comes into play. It's part of being human.

Whilst I concur with most of these observations, I have found that there are some SS setups, such as Devialet Expert/Expert Pro DO sound better over the vast majority of othe SS setups.  The fact that the DAC is integrated into the unit, along with Speaker Active Matching (SAM) does make a difference. 

[RDavidson]

Solid State- Don't think they all sound the same,  but the main factor is if the amp has the power and ability to deliver that to the specific speaker and it's behavior. Once you have that, the differences are small. Decent modern amps pretty much are very low distortion, so that isn't an issue. I think there are many amps that users wouldn't hear the difference in unsighted listening, because the differences are small.

There are differences, but audiophiles tend to do sighted listening and then highly exaggerate the differences they hear, because some of what they perceive is imagined.

And in sighted listening expectation bias ALWAYS comes into play. It's part of being human.

While I generally agree with you, I disagree that sighted listening (especially when we're talking about components, not speakers) plays a major role in a reviewer's listening. I believe once you climb the amplifier ladder into the realm of stuff that is expertly built and/or where the topology may be unique or proprietary, and the parts quality is greater, the sonic differences are NOT subtle whatsoever. A lot of times this gear also looks great. Nothing wrong with that. Who doesn't like nice stuff? If we're talking about midfi amps where most of the parts come from bins and the topology is nothing particularly new or unique, then yes, it makes sense that sonic differences are more subtle between amps of similar pedigree. They may have some unique sonic signature as Letitroll said, but the difference may not be as vast as when comparing expertly built gear.

[twitch54]

Has anyone done "proper" listening tests comparing amps? 

I doubt very few have and as I said earlier if not done in a manner that units were properly level matched it's nothing more than subjective BS.

[rollo]

Even "blind" tests have expectation bias.

   Agree. A simple trick can beat any blind test. I focus on one aspect and one only. Easy to discern the difference. Have yet to be wrong.


charles

[rollo]

I doubt very few have and as I said earlier if not done in a manner that units were properly level matched it's nothing more than subjective BS.

  You are correct. A must for direct comparison.


charles

[avahifi]

At Audio by Van Alstine we can always do level matched double blind listening tests using our ABX Comparator.

It is available right now for $1199

You can connect two sources, two preamplifiers, two power amplifiers, three sets of speakers (with or without subwoofers) and compare any combination in three different modes:  sighted, unsighted, or full test   It is also possible to compare power cords, speaker wires, and interconnect wires. Finally, using two otherwise identical units you could compare different individual component parts.

If you email me (frank@avahifi.com) I will be happy to send you the user manual.

Using our ABX Comparator helps us provide you with the best quality audio equipment at rational prices and takes anticipation bias out of the mix.