Hires 96/24 listening test of opamps

Which of the files do you prefer by listening?

  • rr = LM4562

    Votes: 1 4.5%
  • ss= OPA2134

    Votes: 2 9.1%
  • tt = MA1458

    Votes: 2 9.1%
  • uu = TL072

    Votes: 9 40.9%
  • vv = OPA2134

    Votes: 1 4.5%
  • I can not hear a difference

    Votes: 7 31.8%

  • Total voters
    22
  • Poll closed .
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The API schematic looks like something out of ancient history like a uA702 or uA709 with a power output stage. If by good sound you mean behavior when overloaded or driven into the rails, I would suspect no IC op-amp ever was.
Thank you for taking your time to check the API schematics. It's reasonable to think that API developed their "Opamp" for easier serviceability.

To think an IC was listened to and sent back for $100's of thousands of dollars in layout and masks/wafers based on anything but measurable specs is ridiculous. You will notice the chase for more zeros on the THD numbers for one thing.
I see.


The 627 BTW probably owes its existence to a single customer who I will not name.
Interesting. :)
 
No free parameters magnitude vs time, do you propose some hidden variables that would rewrite information theory, thermodynamics, etc?

Absolutely not. I was responding to what PMA said, which I will discuss further below.

I do object to people using the word excuse, as though there were something to excuse. An excuse is an explanation to try to get of being held to account for doing something wrong. Nobody has done anything wrong or failed to perform in some type of contractual obligation. So, if we are going to wildly go around accusing people of making excuses, I thought the accuser might be interested to see what its like to be on the receiving end. Probably, I should have taken the time to explain my objection more properly, but the way some people seem to receive explanations they don't like is to dismiss them as excuses. In such cases, other tactics to get their attention may occasionally find use.
 
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In isolation it might be. In the stated context I don't think so.


In the greater context of assuming the role of the self-appointed forum pop-psychologist and arbitrator of forum ethics, the whole project seems petty and insulting to others.

We are fortunate to have the administrators we have, which do their job admirably. It's not our place to assume an ex-officio role as one: we are members.

Long and short, if you have a point on the content of a thread, make it and move on.
 
DPH, Although you are currently on my ignore list, I can see your posts if I choose to. When I see one yours right after one of mine, I can expect to find your petty insults directed at me.

I objected to PMA's dismissal of the efforts of various people, not just me, to explain to him problems related to ABX that he apparently doesn't want to understand. Fine, that's his choice. But, I object when he insults the honest efforts of multiple people to explain something by dismissing their efforts as excuses. It's a dismissal and the laying on of a guilt trip at the same time in order to try to goad people into doing what he wants, which is to play his ABX game. I strongly disagree with his assertion that there have been a lot of excuses in this thread, and since he brought up the issue, not me, that opens it up for discussion.

If you would like to stay on point, why don't you address the issue and move on yourself?
 
DPH, Although you are currently on my ignore list, I can see your posts if I choose to. When I see one yours right after one of mine, I can expect to find your petty insults directed at me.
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If you would like to stay on point, why don't you address the issue and move on yourself?

Strange form of paranoia to search a blocked member -- I mean what's the point? And we can disagree on pettiness, I suppose, unless you somehow disagree with my assessment of your posts on diyA? Surely you haven't forgotten your own criticisms of my participation on this forum, no?

Anyhow, my point has long, long been made: with pretty modest electronics, one's rate limiter becomes the speakers, room, and ears. By several miles.

As far as my own assessment of PMA's test: I didn't vote because, after listening to the files nothing really popped out. I wasn't willing to sit down and really focus to give it an honest listen worthy of a "data point".

Jacob2: are you sure a 9/22 score is actually "significant"? Especially given the poor controls on reproduction of PMA's well-prepared samples, and zero instruction on a deciding criteria. The only take-away that seems safe to make from this poll is that the results were a scatter. Yes, I'm sure I could play with multivariate statistics to get a "positive" result, but any sort of conservative analysis, with the attendant understanding that the poll was unstructured makes that seem like a poor decision.
 
There always are on these sort of threads after the reveal.

I'm not so concerned about the excuses, since again as before ABX becomes the villain and soon the argument turns away from the actual results. I'm happy enough again that the usual exaggerated claims are not there. Just Google "op-amp rolling" and you could spend all day reading paragraphs of elaborate prose, "hands over the ears", "sent me out of the room screaming", the wife in the kitchen, etc.

PMA was smart enough to include op-amps that are generally agreed to possibly be marginal in some audio circuits. They were not obvious in "seconds". Possibly a repeat with modern complimentary process op-amps with 100's of MHz GBW, 100's of V/us slewrate and <200 Ohm load drive. would be interesting. ;)
 
"derfy," (1) the so called assessments are without merit and not credible IMO, (2) my criticisms stand.

I was trying to deescalate disagreements using the forum ignore feature, but since I find myself being attacked from behind my back, it may be necessary become more active in defense.

However if there is any desire to deescalate then I am willing to revert to silence on this matter. Otherwise, I guess disagreements will receive more public discussion.
 
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Jacob2: are you sure a 9/22 score is actually "significant"? Especially given the poor controls on reproduction of PMA's well-prepared samples, and zero instruction on a deciding criteria. The only take-away that seems safe to make from this poll is that the results were a scatter. Yes, I'm sure I could play with multivariate statistics to get a "positive" result, but any sort of conservative analysis, with the attendant understanding that the poll was unstructured makes that seem like a poor decision.

Actually i´m surprised as i didn´t wrote that it was significant??

It could be from the numbers (random guessing p=0.2 for each of the five choices) but because the poll numbers were visible before end, independence is not guaranteed, as one poster already mentioned.


Beside that we need disagreement, fruitful discussion where everybody agree with all the other are quite rare, but why not remember the old rule to attack an argument but not the person?
 
To use the usual term, the results so far only mean that the null hypothesis could not be rejected.
Imo we don´t know about the quality of the DA/AD chain as no unprocessed reference was supplied.

Jakob, perhaps I misinterpreted what you meant by this? I read it as you suggesting a non-null conclusion. Did you more mean to say that no conclusion could be reached (results support neither a null nor non-null conclusion)?

If so we're in agreement, and my apologies. And I wrote my explanation to be thorough about my line of thinking, not as an attack on your character (openly acknowledging the obvious acrimony between Mark and myself).
 
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