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John Curl's Blowtorch preamplifier part III
John Curl's Blowtorch preamplifier part III
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Old Yesterday, 04:25 PM   #8061
Max Headroom is offline Max Headroom  Australia
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Location: West Australia, near to the beach, natural ambient sounds mostly.
I have run a set of loopback tests and have interesting results.
Comparing three runs of the same conditions enables pretty good cancellation, ie good record events matching.
Comparing Both Normal to Both Reversed gives lousy cancellation.
Comparing Left Normal/Right Reversed to Left Reversed/Right Normal gives really good cancellation.
I will also compare swapping L and R cable positions next round of tests.

There are still some latency issues as I had to closely time align each recording, this needs closer inspection.
These results repeat what I obtained a week ago, more in the next few days.



Dan.

Last edited by Max Headroom; Yesterday at 04:37 PM.
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Old Yesterday, 05:25 PM   #8062
DPH is offline DPH  United States
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Originally Posted by Jakob2 View Post
But that is much easier to write down as to concede in reality that someone else was able to demonstrate.......

Unfortunately we lost that thread, but without stating (before) what criterion/criteria has to be met by experimental results it will most likely not work as intended.

Thatīs what the "we act like Bayesians (often) without realizing it" implies, if you - deep in your heart - set the prior belief at zero, there will be nothing able to convice you that the opposite is true.
That's pretty unfair to many of us who have to revise deeply seated opinions in the face of new evidence pretty often as our respective fields of research evolve. But as Bayesian analyses imply, it's going to require a very substantial amount of evidence to move the needle.

Now, ask John or Dan to revise their belief systems in the face of abundant fundamental evidence to the opposite. Do you realize how ridiculous this all is?!
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Old Yesterday, 05:27 PM   #8063
DF96 is offline DF96  England
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Quote:
Originally Posted by Max Headroom
How is this so when the only changes are cable direction and minimal, hopefully nil positional change.
If the cable is of sufficient length then you can do things like vary the characteristic impedance along the cable. Then it behaves differently in the two directions - but of course the cable is now asymmetric so this is unsurprising. The same trick does not work for short cables (e.g. domestic audio).

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In metallic conductors, impurities, crystal boundaries and dislocations are causes of noises.
They are causes of resistance, which is a cause of thermal noise. I have seen nothing to suggest that they are sources of excess noise, which seems to be very small in metals. Given that thermal noise in an interconnect is negligible, anything smaller than this must be super-negligible.

Quote:
What does annealing and cryo treatment really do to metals etc ?.
It can make a significant difference to some mechanical properties, and an insignificant difference to electrical properties like resistance.

Quote:
Originally Posted by indra1
Were you not saying that there could be defects in cables (wire and connectors) that may result in directional property within the understanding of physics?
Only if the cable is long enough that transmission line behavioir becomes apparent, and only if these defects are asymmetric.

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I hope some of us can work together like the people of CERN to find a reliable way to obtain hard data on the subject. Tasking the onus of proof to cable proponents has been so far unproductive.
When you find some evidence we will be pleased to consider it, especially if a plausible explanation can be offered too.
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Old Yesterday, 05:56 PM   #8064
jneutron is offline jneutron  United States
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Quote:
Originally Posted by Max Headroom View Post
I have run a set of loopback tests and have interesting results.
Comparing three runs of the same conditions enables pretty good cancellation, ie good record events matching.
Comparing Both Normal to Both Reversed gives lousy cancellation.
Comparing Left Normal/Right Reversed to Left Reversed/Right Normal gives really good cancellation.
I will also compare swapping L and R cable positions next round of tests.

There are still some latency issues as I had to closely time align each recording, this needs closer inspection.
These results repeat what I obtained a week ago, more in the next few days.



Dan.
Time align???

Just hearing that phrase tells me you have no control over your experiments.

You should be using a single mono source, you should be using the amp output difference as the metric. That is as sensitive as you are going to get.

Oh, and use dummy loads. If you are using speakers, the room reflections will impact the difference signal due to room reflection patterns, and you in the room alters that pattern as well.

Without the knowledge base, you are not going to be able to build an accurate test.

I'm glad to see you trying something, but you do not understand the confounders that ruin your tests.

Jn
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Old Yesterday, 05:57 PM   #8065
cbdb is offline cbdb  Canada
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Originally Posted by anatech View Post
Hi cbdb,

I'm agreeing - right?
Yes fully agree.
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Old Yesterday, 06:19 PM   #8066
cbdb is offline cbdb  Canada
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I wonder why the expensive audio cable manufacturers have no real test results on directionality. I'm sure they are aware that real proof would help them sell more cables (and maybe even get them on the list for a Nobel prize ). The only reasons I can think of all point to there being no such phenomenon.
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Old Yesterday, 09:53 PM   #8067
indra1 is offline indra1  Indonesia
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Originally Posted by DF96 View Post
... When you find some evidence we will be pleased to consider it, especially if a plausible explanation can be offered too.
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