That is true, but if you could go back 10, 20, 30, 100 years with today's most advanced kit you would be considered a god and 20, 50, 100 years from now it will be considered quaint.
Take Kunchur's results. He had to go to some serious efforts to get equipment that did not confound the results he got, and still he thinks his results are limited by his equipment and not the limits of human hearing.
dave
I was experimenting with different contact coatings as far back as 1986, with a silver interface between gold and copper. It looks dull, and scuffs easily. Works OK as a contact. Direct gold over copper plating was introduced about 1980 by Japan. We have had the choice of copper-nickel-gold or direct copper-gold RCA connectors for about 30 years. Even with this selection, we have found that connector shape and volume seem to make a difference. This is why some RCA connectors appear stripped down and more basic, today, rather than extra substantial. Why this is so, I have no idea. However, any connector with substantial magnetic attraction to a magnet is off limits to serious hi end designers.
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I think you are suggesting I hook a cap between the hot and ground pins? If so, sure, but there isn't any point. I already know it won't do anything noticeable. We already know what our power supplies do, and how ripple on incoming AC affects our signal (it doesn't) since we designed the power supplies to reject as much incoming noise as possible.
Oh, and even if the cap does create a short, the instruments and circuits will be fine. We have tons of short circuit and ground fault protection so that nothing like that could cause problems with our instrumentation.
Still, I already know that the EMP from the YAG across the room has a MUCH larger effect on my signal than anything else in my lab (assuming all of the room lights are off). Incoming AC noise is irrelevant to my instrumentation, unless it is something huge like a brown out or lightning strike.
Funny story that happened in another lab in my department that seems applicable now: There was mysterious source of noise that nobody seemed able to track down. It was intermittent, lasting for a few seconds, sometimes a little longer, but not more than about 20 seconds or so. Sometimes it would be on for a couple of seconds, go a way for a few seconds and then back on again for several cycles. Sometimes it would be off for several minutes, but it would always come back eventually. The usual suspects, cell phones, printers, cordless phones, other lab equipment, were systematically ruled out. It wasn't until somebody noticed that the noise was most prevalent early in the morning, and right as everyone was leaving for the day that they finally correlated it to the movement of the elevator across the hall!
In a related story, a different lab decided they needed as little noise for one of their super spiffy new instruments as possible, so they built a room sized Faraday cage in which to construct their new instrument, and yes, it does look really cool. They got the instrument up and running, and found that the switching noise from the PSU powering their data acquisition computer was showing up in their signals! They had to custom build a linear PSU for the computer that ended up, not surprisingly, being much larger than the computer itself.
The moral of the stories? All of the systems that went into these instruments were powered by cables costing about $4.25, (which is what what our in-house electronics shop charges for standard "NEMA" power cords, as they are referred to around the building.) Assuming, of course, that they didn't already have some lying around that they got for free. 😉
Neat stories.
But the bipolar cap should only be involved with the ground pin. And you should be able to connect the loose end back to the captured end, as a shorted capacitor, at will. Making no promises or suggestions here, but there does seem to be some anomaly present in ground side electron activities. Just wondering if equipment as sensitive as yours might show some deviation from expected behavior.
Bud
But the bipolar cap should only be involved with the ground pin. And you should be able to connect the loose end back to the captured end, as a shorted capacitor, at will. Making no promises or suggestions here, but there does seem to be some anomaly present in ground side electron activities. Just wondering if equipment as sensitive as yours might show some deviation from expected behavior.
Bud
I don't think that's what Bud means.
I would guess that Bud is saying connect either 1 or both leads of the cap to ground.
dave
Edit: i see that Bud beat me to the submit key 🙂
I had not heard of that conference, but it sounds quite topical! I poked around some of the abstracts, and it was definitely enlightening to see the problems/topics being addressed. Thanks for the additional tip.
Sorry, I am still a little confused. I may have to draw this out, but are you saying to do this? (note my mad MSpaint skillz!!!)
Attachments
I believe that is the scheme yes. You might look at the groundside electrons for some background.
dave
dave
Yes, exactly that. It is just that this is a rather confusing idea. And one that makes very little sense, but might lead to some interesting results, or not. But if not, then we can close the door on one of the claims of power cable activists, at a level of sensitivity well above the equipment their oils are meant to lubricate.
Bud
Bud
Well, like I said, I know that I won't see anything, but I'll be happy to try. Not sure what caps I have lying around, so we'll have to see. I may be able to borrow a goofy film cap from the shop tomorrow for a few minutes, just for fun. Any suggestions?
If I have time, I'll try putting the cap on my PMT amp, and compare 256 averaged transient absorption scans of free base tetraphenyl porphyrin, which is a standard we use for that instrument. I can block most of the signal intensity so that I have to crank up the gain on my scope. I think I can drop the signal to a few millivolts coming out of the high gain stage of my amp while still getting a recognizable transient over the noise. Would that get you what you are looking for? I don't typically run like that since I usually want all of the signal I can get, but I will try and bias the experiment towards lower signal to noise so that we can get better resolution of the noise itself. Alternately, I can put the cap on the input to the power supply for my PMT. That could arguably be a bigger source of noise than my amp, but I figured we were talking amps here, so I would keep things as simple as possible.
Hmm. . . I think I'll just try a few things, say the experimental conditions, and let people draw their own conclusions. It's definitely time for bed, so I guess I'll think about this more tomorrow.
Edit: Just to be really nasty, I'll repeat the same test, this time moving the amp housing 6 inches to the left on my bench, just to mess with people. 😀 That will be fun! I already know what will happen, but it may be enlightening to some folks out there. . . .
The talk of grounding made me think of another story, though. I wasn't present for this one, but I have heard the tale repeated many times. . . .
Back in the 70's, one of the well respected professors who designs instrumentation was not happy with the stability of his electrical ground. The ground potential was drifting, and since he was frequently taking single ended measurements of whatever it was he was studying at the time, the data was floating around causing no shortage of problems. Eventually he decided that he needed a "better" ground that was more stable. He had the department dig up a big area of dirt behind the building, put down a big wire screen connected to a cable, coated the screen with conductive salts of some sort, and reburied the whole thing. He had the cable run back into his lab, and low and behold it actually worked! (actually, not really all that surprising since it was a pretty good "ground" source no matter how you sliced it). After he went through the trouble of getting it set up, every lab that had instrumentation tied into the screen and had an "instrument ground" panel installed. To this day, there are still panels of green 5-way binding posts scattered through the building with engraved "Instrument Ground" signs. Not too many people bother with them any more since so few of our experiments are referenced relative to an absolute ground, but it is interesting to see what was needed "back in the day" to get good data.
The idea that ground noise can have an impact on signal integrity is not only feasible, but has been very well established. With most single ended audio signals, like those carried on standard RCA cables. for example, noise on the ground will most definitely impact a signal. The solution is to use balanced connectors, not a goofy power cable or osmium coated RCA plugs! But what the heck do I know. . . .
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'But what the heck do I know. . . . ' dfdye
I think you know a lot about the things that really matter. I Enjoy your posts.
I think you know a lot about the things that really matter. I Enjoy your posts.
Fraudulent claims about cables are at the heart of this debate. The consequences are people parting with their hard earned cash under false pretences.
You said: “..he deserves to be ripped off”. That’s a surprising thing to say. No one deserves to be ripped off. Indeed, every consumer deserves to be told things in good faith, which are accurate and not deceptive. You also make statements about consumers being “foolish”. But there is information asymmetry between consumers and manufacturers, in favour of manufacturers. That is the reality that all consumers face.
You say that its up to consumers to hear the difference and therefore not to be deceived. But that is naive. How are consumers to know if one cable is better than (many) others, when the engineering says the differences will be either slight or non-existent? How are they to make those judgements? Consumers do not have the resources to conduct independent lab tests or organise listening panels to test claims about cables. Nor should they. Just like we don’t expect car consumers to purchase five or six similar cars and crash them into walls to validate the claims about safety by car makers, we should not expect consumers to do the independent, objective testing that manufacturers ought to do to show that their claims are not fraudulent.
It used to be that consumers could turn to audio magazines to get some advice on products. Sadly, it seems that the subjectivist camp now rules the consumer magazines, cutting off one more stream of independent, objective advice that may counter the claims of the cable makers.
The whole point of double blind tests is to bring some objectivity into the debate. Just as a pharmaceutical company can be brought to account for false claims about the efficacy of their expensive “wonder drug”, so too can any manufacturer who makes false claims about their product. Courts weigh up conflicting evidence and make judgments all the time, that’s their job. It’s just a pity the consumer protection agencies haven’t taken on some of these claims and tested then in open court.
No need to summarise the faults in dbt as you see them. I’m not asking for that. I’m asking for your specific test protocol for determining if two cables sound different. Your turf now. If you can’t provide one then you should be open to the possibility that the double blind test is the best one we’ve got at present to help separate false claims from true ones. If you’ve got a better one, tell us about it.
None of these examples have any relevance to (most) commercially available audio equipment. Of course it would be possible to build power supplies that are not sensitive to mains noise, problem is that in commercial hi-fi equipment, not many are. Perhaps for exactly this reason "if it doesn't influence medical or space equipment then there can't be a problem", so it just get ignored.
To build a noise proof power supply for a high power amplifier, that doesn't also have a negative influence on SQ would be rather costly, on low power equipment it is much easier.
No, we are talking about if cables can make a difference on SQ. If you want to discuss ridicilous prices and fraudulant claims on cables, perhaps start a new thread, you may just find that nobody is going to differ with you. 😉
That's the price of foolishness, hopefully he will realise it and do his homework first in future. 🙂
I don't believe anybody would buy an expensive car without a testdrive and getting some other important information first, who would buy expensive cables just because some advertisement claim something special? Come on, give other people some credit for their intelligence also, I know it's difficult sometimes though.
It's actually very easy, just compare your existing cable with whatever you are interested in, on your own system with your own ears. If it sound the same or worse, just return the cable and smile, if it sound better, feel sad and decide if it is worth the extra cost. Not that complicated is it?
What has advertising got to do with listening? I again will say that I have never sold anything to anyone that did not have an opportunity to audition said cables in their systems. What do people have against people listening to what they are purchasing? Measure what ever suits you, but the differences are there, if you choose to listen and your system has the resolving power to allow you to hear the differences. Not everything is good, no matter what it costs in every system. One has to first allow themselves an opportunity to learn to listen, or else nothing will ever become evident, except that they have closed minds and are the real idiots.
Very interesting, do you have more information about this? I guess this may explain at least part of cable 'burn-in'. Something strange (perhaps not), I've found that 'single crystal conductors' or whatever it's called, take longer to burn-in than cables using 'normal' conductors.
Thanks for sharing your test results.
Hmm.... is that what you would say to someone who brought back a cable saying they couldn't hear any difference? They just haven't got a system with the "resolving power"...nice sales line for upgrades.😉
So, if you can't hear the differences, you need to "learn to listen" and "open your mind". I'm sure you do not mean to be patronizing, but that is how these statements come across. They could almost be said by a salesman trying to intimidate a newbie into buying expensive cables (again I'm not saying you have that intention).
But you can see how people could be put under pressure to hear things that were not in fact there, by using these phrases to place the lack of ability to hear the claimed differences back onto the consumer. Whereas we need to reverse the onus of proof, so that the companies making the claims for audible improvement are the ones that need to prove their cables can pass properly designed tests that show an audible difference.
The two issues are conjoined. Manufacturers claim that their cables make an improvement to sound quality. That provides them with the rationale to charge significantly higher prices than standard cables.
Sure, people should do research. Just curious, what source of objective info about audio cables is currently available for the non audio engineering consumer? Hardly any. Certainly not independent test reports using validated protocols.
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