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The famous AB test between amplifiers

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Although I'm not sure what the point of this thread is, I'll play a long for a just a little bit:

One would think ASR types would consider such an amp broken, but they often don't. Why? This sort of thing is not always easy to catch in testing. I'm not about to read 52 pages of comments for an amp I don't care about at all, but the Wiim Amp clearly has this issue, and it is noted in the review as "load dependency". Since it appeared to impact 20kHz, no one cared. But just how problematic the load dependency is did not get fully captured in basic tests here because ASR does not use a complex load. To date this amp has a 85%+ "Fine" or "Great" user rating. I just slapped a "Poor" on it because it really does suck that bad by any objective measure where "potentially audible issues" is the standard. It's miles worse than the boat of of amps with 78dB SINAD that get regularly panned. Unfortunately, it can be hard to tease this out unless you get really in depth on the testing, and understand what measurements mean. EAC got more in depth, and found significant response deviations on complex loads of up to 1dB. A lot? No, but it is enough that you're almost guaranteed to hear it on certain program material. Is it broken? Yup. Did it get panned here? Nope. Not as hard as it should have. And I'll bet you LOTS of people bought it. Even when the EAC review came up, most of the comments there were about output power issues. Not the load dependency. And this is forgivable, since the load dependency even at (potentially) 1dB will still be hard for a lot of people to detect.

So, what's the point of bringing this up (other than my weeks long theme of picking on people for being obsessed with measurements but often not understanding them nearly as well as they ought for people obsessing over measurements)? Well, let's go back to OP's question about the Carver amp. My recollection (and I think someone mentioned) that the bad SINAD was mostly distortion. The SNR is actually not that bad. So there's not going to be anything obviously amiss. On plenty of program material, over plenty of speakers, I would venture a guess that 60% of listeners, at least, would fail to differentiate the amp when used within its limits. But there's some load dependency there, too, so like the Wiim amp, it's going to have frequency response deviations. Now, you take a trained listener with proverbial golden ears and hook both amps up to a set of extremely low distortion speakers? They'll probably nail the Carver it every time. Whether the distortion will be objectionable is an entirely different matter.

Now let's add another layer: Play some symphonic material with 20dB dynamic range. Turn up the volume. The Wiim is easily driven past its modest limits. The Carver is still cooking. The Carver even with all its distortion will be a far superior amp to the Wiim or any other low powered toy amp, and audibly so. Now toss a decent Class AB amp in there. Depending on the speakers, you might be able to pick it out from the Carver. In fact, you probably will with careful listening since the Carver just has that much distortion. Will it sound better? I have no idea. But it will sound more accurate. But now go and throw almost any other quality AB amp into the mix with similar output power. Your little project just got much harder.



In the end, OP END_WAY, you're trying to distill a question with a complex answer down into some simple Yes or No answer. It's not that simple. At what level can you differentiate? Totally depends on the acuity of the listener, the quality of the speakers, potentially the load presented by the speakers, the volume level selected, the program material, you name it. At what level is "good enough"? Assuming flat response and sufficient power not to clip or vary into the load at all impedances and phase angles, probably way down at like .05% THD from 20Hz to 20kHz and 65db or 70dB unweighted SNR (if not worse) at 1W, on insensitive speakers. In other words, a lot "worse" amps than most people here probably think they need. Only the odd man out is going to be tell much of a difference past that.
If you like loud, get a big amp simple.

I’m looking at Wiim amps, waiting for the pro.

I generally treat music as background. TV and movies are up a bit, but never to theater levels. I set the volume so the dialog is about the same as a loud person in the room, and everything else follows.

Streamed soundtracks are hit or miss. I watch everything from old TV to 4k movies.
 
I think the idea that most people here think they need some 100db or more SINAD is way way way over-cooked (usually by people who have a bone to pick with objectivity in general). I don' t think it's needed. But it can easily be had for no greater expense so why not?
 
Although I'm not sure what the point of this thread is, I'll play a long for a just a little bit:

One would think ASR types would consider such an amp broken, but they often don't.

We're talking about an amp that under non-over-loaded, normal operation circumstances is not flat. I don't think many here would suggest that's a good thing.
 
We're back to the same thing, so all properly built amplifiers sound the same across the frequency range, they have the same dynamics, they have the same timbre, they have the same musicality, they have the ability to handle the complexity of a speaker at different impedance loads, meaning there are no sonic differences that you can hear, is that how you think it is?
Wait, you left out PRAT. Fail. :rolleyes:
 
I could tell you the same thing, in all your posts, absolutely in all of them, you give an erroneous opinion and my argument is that nobody in this world has the absolute truth, even if you think you are right, including the measurements.
The thing is that when someone comments on something that they don't like because it is shown from another perspective, everyone wants to intervene and boost their ego by wanting to belittle the opinion of others.
Do you think science demands 'absolute truth'? It doesn't.

What we have are probabilities from observed reality. And these can be very, very lopsided -- the probability of A can approach 1 and B can approach 0. Like, you're gonna die someday. Very, very, very close to 1 on that.

We are telling you things about amps and psychoacoustics that have good empirical/experimental support. That means their probabilities of being true, if one could calculate them, would tend more toward 1 than 0.

Whereas you literally don't know what we are talking about . Blind test rationales and protocols, and JNDs (just noticeable difference) seem to be new concepts to you. And that means you don't know what you're talking about, either. Suggest you post less and learn more.
 
AB testing anything is almost an instant fail. Unless you are talking about fairly large differences. Small differences ge lost in our hearing and our brains. Try as much as many people try (even on ASR) to think they can outsmart their brain, it can't be done. The brain ALWAYS wins. Well, unless you are a Scarecrow in Oz. :)
 
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