John Curl's Blowtorch preamplifier part II

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Again, with all this experience here, and expertise, has no one ever heard an SPDIF cable change also change the subjective sonic presentation enough so as to be noticed??

Never noticed that. But I wasn't trying to notice it either. However, cables can be a source of clock jitter. If no reclocking occurs on the receiving end, then I suppose there might be something to hear.
 
Step up, and share your experiences?

Nope never heard any of these wire/connector swaps produce any change. The only thing I was able to convince myself was possibly audible was a very large change in output stage standing current over to 25W of class A in a 100W amp. Oh yes the shorting strap on my speakers came off and one channel had no tweeter, I did notice that from accidental blind listening alone.
 
Randi (seemingly) always does that.
He makes the challenge,
then after trying to put up a whole set of paranoid barriers to keeping people from hearing a difference,
finally withdraws or the other side gives up in finding a reasonable test possible.

the good news is,

the crank has been forced out.

literally.

James Randi retires from foundation at age 86 | Doubtful News

he did not want to leave,

yet,

the mess he was about to perpetrate would have been unacceptable .
 
<snip> Serendipity is great (and usually necessary) to build the hypothesis, but it needs testing before it can be asserted with any sort of confidence.

I totally agree, to be really certain (means high probability) a scientific approach is needed. But to think that it would change anything in our discussions in this thread would be naive. Sad but imho true.

There is the old aphorism "a believer does not need a confirmation, and no confirmation will ever be good enough for the non-believer" .

I´ve started with controlled listening tests back in mid 80s after reading some articles by Dan Shanefield, who imo brought the concept of "blind tests" into the audio field wrt multidimensional perception/listening. His approach was reasonable and his argueing convincing; so i started with it and could confirm my listening impression from "sighted listening" under blind test conditions, But noticed at the same time that my collegues, although having the same impressions before as i did, had difficulties to succeed in the sensory test, which changed after some training under these new conditions. During the last 30 years i´ve done a lot of controlled tests myself and conducted controlled listening tests with roughly 120 participants. Does it help in these discussions? Of course not. Or, better said it depends on the results. Rising lines of defence (in case of unpleasant results):
-) was it published? No? Well then....
-) was it peer reviewed? No? Well then ....
-) it was peer reviewed? Ok, but it was the wrong peer group (they should have asked others who really know.......)
-) fine with the test, but is there a convincing theoretical reasoning? No? Well then....
-) who did the test? You did it yourself? Well then (paycheck depends on ).....
-) an university ran the test? Ok, but who paid for the effort? You? Well then ....

And of course, as there is no perfect test, there is always a reason for doubt and the results are only probabilities.
And in the end, does it really matter? Imho not, because high quality audio replay is a niché in a niché . No one will gain (probably) more sales due to the results of controlled listening tests, so as long as it is not officially required....
 
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Nope never heard any of these wire/connector swaps produce any change.
The only thing I was able to convince myself was possibly audible was ...

i wonder whether anyone who might say this,

actually likes music ...

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If you are talking about the metal corrugated one, it is consistent with a microwave lens.

The theory is that the velocity of propagation between the parallel folded metal sheets is lower than air. So the structure is delaying the sides moreso than the middle. This results in a more cylindrical horizontal wavefront which causes more horizontal dispersion.

In microwaves, they will use a variable density (or permittivity) structure in front of the beam with the intent of changing the prop velocity to alter the wavefront shape. I've seen them used at the receiver horn end with sub mm equipment.

John

Thanks John!!!

I'm with Bonsai on ferrites, still waiting for real evidence that they are detrimental, not just anecdotes. It does say a lot when believers in Bybee's say ferrites muddy the sound etc.
In fact i will go further, its a bloody joke when proven technology is dismissed and fantasy scam products (BQPs) are lauded...
So some real proof would be nice...

I'd like to point out JC did post a measured difference with Bybee's, and it was dismissed - surely to maintain proper social biasing on the forum?

Also I've recently discovered some of the benefits of the Bybee's may be from dampening that occurs either do to their resistance, or a combination. In which case a resistor would actually have a benefit to sound. Now, I've never heard or seen the Bybee device Bear is talking about. But I believe he heard something.

When I make a change and I'm not sure it did anything, I'll wait for awhile before I change back. If I'm still not detecting any difference then it likely just says where it was prior; or with whatever fits the math best (if available). I can't perform a double blind study every time I change something, but I give a good effort to use the one tool we always have, familiarity. This has led to countless rejections; including ferrite clamps.

I assure you my aim isn't to be argumentative, or counter-measure, anything of the sort. I'd gladly adopt ferrite clamps and start slapping them on everything, if the result was good. Maybe ferrite beads cause a resonance? Any which way, I await for someone to unlock the secrets for me because there's so many other places I can spend my time that are consistently beneficial.

Why? two thought:
1] Self fulling expectations.
2] The ferrites removed a small amount of background noise that you had come to enjoy.

Now this super amusing. I'm being called a nut job here, when this is written? I can't wait for the explanation of why I make all sorts of measurable differences in noise, with lots of methods, it never sounds the same as when I put on a ferrite clamp. Why do ferrite clamps have this magical ability to remove background noise that every other form of noise reduction does not? :boggled: But at the same time at least I can respect Kevin since he's trying explain a possibility instead of calling for an exorcism of the blasphemy that is using your ears to listen to music.
 
As he should have been advised in the first place, cables at the extremes of L and C can and will cause easily audible frequency response deviations. IIRC narrow band equalization to better than .1dB was not part of the challenge.

Does that establish an excuse for his behaviour?
As both parties agreed on a scientifically valid approach it could have been easily included that the deviations had to be below the usual hearing thresholds. And otoh if that was already questionable Randi should not rant about "supernatural powers needed" .....

But they got never to the point of negotiating something like that, as Randi weaseled out before ..... :)
 
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