John Curl's Blowtorch preamplifier part II

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#86,401
Jakob2 said:
@ DPH,

did you really write "No" ? 🙂

What you proposed is known as "triangle test" and it _is_ a different test than an "A/B- test" (known as paired comparison, abbreviated 2-AFC if forced choice or 2-AC if the no preference/difference option is included).

As said before, it exists a plethora of literature about sensory testing, obviously just to be ignored. 😉
Click to expand...

Triangle and tetrad protocols: Small sensory differences, resampling and consumer relevance

This, along with what else I've read surely says that a triangle (I'm right here admitting that I thought those required forced choice and prior knowledge that there were 2 identical samples) and tetrad protocols are much, much, MUCH more powerful than binary tests. So I missed the semantics, but didn't lose sight of the importance of controlling your data.

In short, controls are good for testing--to ignore them is to lose a huge amount of statistical power (and thus require much broader populations and number of trials).
 
#86,402
<testing, testing, 1,2,3,4... testing> </testing>

Is this thing on?

Still really would like to know which 2 or more "blameless" amps are indistinguishable in sound, sighted or DBT/ABX...

For example, you would have to be willing to run one model/brand amp on one channel and another on the other... anybody willing?

...remarkable reluctance to take a stand on this silly question... must be, what? too parochial, too simplistic, too improperly stated?


Now for something not completely different...

back in the day, the Bryston amps were referred to as "Brights-ton". Referring to their obvious sonic character. Not sure how more recent models from that company are doing or not.

Could this have been a limiting/confounding factor at Harmon??
Did they never haul in a super-ultra high performance amp just to check??
Halcro? Something like that?? Maybe one of those big Parasound things??
Anything else other than Bryston the whole time?

So, here's a question, does anyone think the original Bryston amps sound the same as the newer generation of Bryston amps? I don't know.
 
#86,403
:headbash:Have you never run two speakers from two different amps?:headbash:
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#86,408
DPH said:
Probably doesn't matter compared to the Brystons, but there we go!
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An anecdote: years ago Harman supplied the sound system for a big movie theater, perhaps it was one in LA for Cinerama. A golden-ears person walked in and began to grimace profusely and said the sound quality was terrible.

He inquired about the details of the system and discovered that the amps were the Madrigal second-label Proceeds. He said AHH that's the problem those are terrible amps! He suggested Brystons. Harman dutifully changed them out and the man came back and said Ahhhh that's worlds better now.
 
#86,410
bear said:
So the Brystons and the Levinsons sound is indistinguishable from each other? DPH?
Should I start these two as first on the list?

And, did they hear NO difference between the two at Harmon?
Surely they did extensive ABX testing?

_-_-
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The problem about amplifiers and other electronics is that, unless they are known to measure horribly, there is a profound bias in most of the divisions (the Luxury Audio one probably the exception) that electronics are, for all intents and purposes, way good enough.

So I doubt that there has ever been ABX testing of amplifiers. Olive mentioned to me once that he probably was going to have to do something eventually, but afaik that is very low as a priority.
 
#86,411
I was told by someone once who was in sales that his project when at USC business school was to sell the same item in a store at two different price points. The more expensive pen which was substantially more expensive outsold the cheaper one by a wide margin, there were no differences in the pens. This is expectation bias or what, but cost does influence people and the same is obviously true in many products. High end audio plays to that marketing dynamic and JC's product are perfectly positioned to take advantage of that human trait. Nothing against JC or his designs, they are what they are, but price has nothing to do with quality most of the time.
 
#86,412
#86,413
bcarso said:
The problem about amplifiers and other electronics is that, unless they are known to measure horribly, there is a profound bias in most of the divisions (the Luxury Audio one probably the exception) that electronics are, for all intents and purposes, way good enough.

So I doubt that there has ever been ABX testing of amplifiers. Olive mentioned to me once that he probably was going to have to do something eventually, but afaik that is very low as a priority.
Click to expand...

That's a very polite way of putting the message.

Edit: thanks, Mark!
 
#86,414
bcarso said:
An anecdote: years ago Harman supplied the sound system for a big movie theater, perhaps it was one in LA for Cinerama. A golden-ears person walked in and began to grimace profusely and said the sound quality was terrible.

He inquired about the details of the system and discovered that the amps were the Madrigal second-label Proceeds. He said AHH that's the problem those are terrible amps! He suggested Brystons. Harman dutifully changed them out and the man came back and said Ahhhh that's worlds better now.
Click to expand...

Yeah, well... who knows?
Perhaps it was better?

But the key point here is that according to the story that particular person in that particular situation thought they did not sound the same...
...did they sound the same? That's the question.

I have no position on that.
Only my own personal experience thus far.
Always willing to modify and update my knowledge and so my opinions.

For example, I can say that I always thought that horns were intrinsically flawed, and had never heard a good set. Until I did. Then my opinion changed and I began to try to find out why that one did sound good, when all the others did not (to me).

_-_-
 
#86,415
Along those lines, Trader Joe's, long before the days of two-buck Chuck, acquired many pallets of cases of Villa Mt. Eden Chardonnay that the winery was concerned was getting "too long in the tooth". They were sold for I think three dollars a bottle. I must have purchased at least ten cases---the stuff was delicious and I like Chards with a little bottle age, even if some aspects of a given wine might be fading a trifle. I would give bottles away, take them to restaurants (where guests would insist on picking up the tab because I had brought the wonderful wine).

A wine guy at TJs confided in me, while telling me that he probably shouldn't. He pointed out that TJ policy was the well-known practice of keystoning, buy for x and sell for 2x.

But he said We got these for fifty cents a bottle, and we figured no one would buy a one dollar (or 99 cent) bottle of wine and think it could be any good.
 
#86,416
bcarso said:
The problem about amplifiers and other electronics is that, unless they are known to measure horribly, there is a profound bias in most of the divisions (the Luxury Audio one probably the exception) that electronics are, for all intents and purposes, way good enough.

So I doubt that there has ever been ABX testing of amplifiers. Olive mentioned to me once that he probably was going to have to do something eventually, but afaik that is very low as a priority.
Click to expand...

Undoubtedly it is for them.

However, that might change IF the scenario went something like this:

With the usual tests we get speakers: A, B, C, D in order of preference.

BUT, hypothetically, with amplifier 1, and amplifier 2, the preferred combinations worked out like this: 2C, 1A, 1C, 2D (in the last case amp 2 sounded better than amp 1)

Of course they might all sound the same too... but since the scientific method at Harmon does not include such a consideration we will not know until they try this - with a few disparate amplifiers.

If they did it secretly, I'd bet/expect in the the words of Chet Atkins "...there'll be some changes made..."

_-_-
 
#86,417
I went through a phase where I bought nothing more expensive than $10 from TJ's (and I don't drink much at all), and was pleasantly surprised by a number of French table wines. The buyer/stocker there found it fun to work with me as I can articulate my tastes fairly well.

To cut to the chase, I had some I forgot in "storage", I think a couple "TJ's reserve" cabs, for a couple years, so they were getting up towards 5-6 years. Was surprised how enjoyable they were.

Funny, I take the same tack for audio. You can get a lot of value if you know what to do and are in for the fun of it all.
 
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