I've never heard of a GFI that does that. I know code only allows N/G at the load panel, but was not aware such a widgit existed.
How do they look for it, loop inductance minimum?
The RPD's I looked at were simple transient supression. I know load panel transients can do 15kV, and branch outlets 6kV, the 600 joule rating probably means too close to the panel had a history of failing early, they count on the long wire to dull it down.
It could also be they don't have a strong ground bond and too close to the panel with a higher bolted fault current can take it out during a hot to ground short in the RPD unit, leaving the unit shell hot.
John
I have no idea what you want, but my test was about a fair as any could be. The original reference recording was included, along with all altered versions. Listeners were free to use any equipment (usually their own system), any method, any amount of time to hear the differences.
The test had its faults, but fairness was not one of them.
I've used one of those for a few years. Got tired of it as a) there only were very rarely any audible differences and b) in such a case it was mostly a toss-up on which of the subjects was preferable.
Sold it and spend the money on records ;-)
Jan
It's all in the thread. But basically it was very difficult for anyone to tell one file from another, or even from the source file.
The files were produced by a re-recording loop. The source file was played from the output of an M-Audio sound card back to its input. The loop consisted of copper wire, or various other conductors such as bananas, potatoes, a bucket of mud, beer, steel wool, etc.
The reference file was not identified, listeners had to pick which file they though was which material, or reference.
The files were produced by a re-recording loop. The source file was played from the output of an M-Audio sound card back to its input. The loop consisted of copper wire, or various other conductors such as bananas, potatoes, a bucket of mud, beer, steel wool, etc.
The reference file was not identified, listeners had to pick which file they though was which material, or reference.
How was the source file produced, a commercial recording? Recorded using the M-audio?
EDIT: So far I am wondering if the whole thing was manifestly unfair. Were people trained in some way to identify the sound of mud, bananas, etc.? Otherwise, how could they possibly identify such things by sound? Was dynamic distortion of the M-audio path accounted for in some way to exclude it from masking differences in sound of the various test conductors? And so on...
EDIT: So far I am wondering if the whole thing was manifestly unfair. Were people trained in some way to identify the sound of mud, bananas, etc.? Otherwise, how could they possibly identify such things by sound? Was dynamic distortion of the M-audio path accounted for in some way to exclude it from masking differences in sound of the various test conductors? And so on...
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Strawmen. Are all the 'audiophiles' that report sweeping changes from a different capacitor, wire etc trained to identify sound differences?
Are you also suggesting that the dynamic distortion of a well-regarded M-audio set is higher than a possible difference between a potato and a good interlink?
Jan
Are you also suggesting that the dynamic distortion of a well-regarded M-audio set is higher than a possible difference between a potato and a good interlink?
Jan
Geez Mark, You could go read the thread. You are way overthinking it.
The two related problems were technical, not psychological or procedural. But they did make a difference.
- Yes, snippets of commercial recordings.
- No one was trained to identify the sound of mud, potatoes, etc.
- No, the M-Audio card was not compensated for in any other way than level (and in some cases, noise).
It didn't matter, the point was to listen for ANY difference and for fun, guess what it was - Identification of the reference file vs looped was difficult. The re-recorded files were not obviously distinct from the reference.
The two related problems were technical, not psychological or procedural. But they did make a difference.
I don't know, if you read it as such, but it was in no way meant offensive.
My comment was related to the term "fair" in the broadest sense along the line "if an audible difference exists it would have been revealed in this test" , thinking that the term "fair" was used as a synonym for "best" .
To address the uncertainty, I wrote in my post about the need to define what "fair" means in this context.
Could you please post a link to the original thread?
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No claim for best, only a test that is not rigged or crippled.
Here is the thread:
https://www.diyaudio.com/community/...bout-a-potato-or-even-mud.236248/post-3497210
After doing the test, I took it ot work as a parlor trick. We used a microphone and a friend with a "radio voice" as the source, which went thu a mixing console then out to a powered JBL speaker. A potato was inserted into the signal chain to general amazement that it conducted the sound just fine.
To top that, I held the potato in my left hand and then held the hand of the next person in a chain of half a dozen people. The sound of the mic went thru the potato and all of us back to the console and speaker. Great fun was had by having someone in the chain drop hands - and the sound stopped.
The point of that test was just a demo, not sound quality.
IME experience audiophiles learn to identify sounds of devices sighted first, after that they may try to identify a device blind. IIRC that's more or less what PMA did when he trained himself to pass ABX.
Also, I am questioning, not suggesting, that the M-audio might possibly have masked some small differences in sound. IME recording interfaces are not perfectly audibly transparent, therefore if doing such a test myself I would probably try to determine if there was an audible difference without going through the recording interface. If there was, even slightly so, then I would want to verify the same slight effect was equally audible on the recording produced by M-audio.
Just didn't get to it yet. Was it a snippet or a full recording? In other words was it edited at all by some software? If it was an unedited CD rip then I would have to wonder about the reproduction equipment used by listeners participating in the test (and might wonder about that anyway). If their DACs masked differences then it still might be true that if they stuck a potato or some mud in the analog audio path after their DAC that the resulting sound difference would not be masked. It would be something else to investigate, or at least a possibility to consider.
Member
Joined 2006
Well... if one looks at what's behind the cause of resistivity in metal copper.. it's basically the scattering of electrons off from the metal ions...
Misorientation of the copper grains forms dislocations at the grain boundaries which will just give more but similar kind of electrons scattering, so higher resistance results and thats pretty much it, unlike other kinds of potentially more hazardous imperfections that might exist along the path of the electrons transport....
The subject of surface states of copper imho actually causes more harm relatively speaking, particularly at the interface of copper wire and the plastic jacket where electrons flowing near the surface could be trapped and only released later in a random fashion.
btw, copper oxide formed on the copper surface is a semiconductor, it rectifies the signal, but of course in the microscopic sense, so watch out for the higher freq content. 😁
Misorientation of the copper grains forms dislocations at the grain boundaries which will just give more but similar kind of electrons scattering, so higher resistance results and thats pretty much it, unlike other kinds of potentially more hazardous imperfections that might exist along the path of the electrons transport....
The subject of surface states of copper imho actually causes more harm relatively speaking, particularly at the interface of copper wire and the plastic jacket where electrons flowing near the surface could be trapped and only released later in a random fashion.
btw, copper oxide formed on the copper surface is a semiconductor, it rectifies the signal, but of course in the microscopic sense, so watch out for the higher freq content. 😁
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Something else to wonder about: Might eddy currents force current flow laterally across wire strands including through copper oxide surface contamination? One manufacturer of audiophile OFC wire hermetically seals the strands within the (also halogen free) jacket. Other people use parallel strands of enameled wire to prevent current from flowing between strands in the first place.
Snippets. You can go look, but I think I finally took the files out of the cloud.
Yes, it was cut and pasted together in a wave editor. I made very sure that the process was bit perfect. The editing was not an issue.
Of course. But that is an objection very frequently leveled at tests. In this case, the listeners were free to use any system they chose. The point being that if one was listening on his own system, were it was claimed great differences could be heard in cables, why weren't they heard in this exreme test?
Yes. See above. But that's the point. Can you, on your system (or another) on which you claim that you can hear obvious differences in wires and metals, tell the difference between a recording thru copper, or banana or the reference. If you can hear the difference between different types of metals, then my test should be extremely easy. It was not.
Member
Joined 2006
Dont think that's of a concern....as long as they contribute to the current conduction collectively... Ekectrons like to take the path of less resistance, to reach a lower energy state though.
In the case of having enameled strands instead.. I think that's more like a Litz wire configuration... a method to minimize the impact of skin effect (where high freqs travel towards the conductor surface)
In the case of having enameled strands instead.. I think that's more like a Litz wire configuration... a method to minimize the impact of skin effect (where high freqs travel towards the conductor surface)
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Two thoughts about the above:
1) PMA gave me an honorable mention in one of his listening tests for sorting recordings of unity gain noninverting buffer opamps in order of distortion by ear, fully DBT. So, on my system I would say if mud or bananas change the sound as much more than some very low distortion opamps then I could likely hear it. That assumes your recording gear is as good as PMA used.
2) Not sure if you missed my point that people may be able to hear differences in wires, capacitors, etc., in the analog chain folllowing their dacs. That doesn't mean their dacs can reproduce such subtle differences in recordings. IME most dacs are not transparent and fully revealing. They may measure quite well in steady state distortion tests, but that's not all there is to it. That's something that may get measured in large part because its easy to measure. Harder to measure non-steady state distortions and noises are not given by the push of a button on an AP machine, so we usually don't see measurements of those things.
Thanks for the link Pano.
I've just browsed through the first pages and think at first it were MP3 files and later FLAC (original recording in CD-resolution) used.
You've listed on page 3 some results from six listeners, one couldn't tell any difference, while 4 out of the 5 remaining correctly identified the original file.
Am I mistaken?
I've just browsed through the first pages and think at first it were MP3 files and later FLAC (original recording in CD-resolution) used.
You've listed on page 3 some results from six listeners, one couldn't tell any difference, while 4 out of the 5 remaining correctly identified the original file.
Am I mistaken?
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Didn't miss it, but it wasn't the point of the test. If you can't tell the difference between the reference file and one that's been looped thru a lot of "junk" - just how good are your ears and your system?
Telling the difference between a banana and a potato is silly, of course, who would know? But not the real test.
Quality post DAC becomes a minor concern if your DAC and the following electronics can't tell the difference. Or if your ears can't. The test puts all the wild claims about silver vs copper vs special copper in perspective. FWIW, I do believe that parts make a difference, but I no longer give any credit to the wild claims.
The test was done in the way that the vast majority of audiophiles listen to music. The way in which so many claims of audibility for cables are made.