jlsem said:
You can probably search for my sad story. After that experience, I am permanently soured on Teflon cables.
Or, if you're ever down here in Austin, I can do a quick demo- I still have some Teflon/silver interconnects that are terrific microphones.
edit: Here it is, straight from the non-tweakiest guy on the forum:
http://www.diyaudio.com/forums/showthread.php?s=&postid=1484644&highlight=#post1484644
92R?
We used it for Am radio transmissions - I forget the maths now, but it was a better match into a dipole, AFAIR.
We used it for Am radio transmissions - I forget the maths now, but it was a better match into a dipole, AFAIR.
Don't think so. It's about 0.125" diameter, silver-plated copper conductor and shield. Never measured the characteristic impedance.
scott wurcer said:
Computer industry if I remember correctly. What do you expect from people who standardized on 100 ohm Twinax?
I don't quite understand why the outer conductor on the co-ax wasn't able to shunt the static build-up to ground. Or am I missing something? Also, is your post implying vibration caused by the signal or just general vibration from living in SF? Other insulators exhibit triboelectric effects but I still don't have any "values" to compare.
John
The inner and out conductors are insulated from one another. With any vibration or motion, a charge is formed, which is equivalent to a voltage between the center conductor and shield. "Ground" is just a reference point in this context, not a place to drain charges.
Presumably, I could avoid the problem by suspending the cable in a way that isolated it from any possible vibration. Or I could chuck the cable and put in one that isn't vibration sensitive. The latter strikes me as the easier approach.
The vibration I referred to was external mechanical vibration being transduced by the coax. Music tends to rattle things around. I seriously doubt that the microamp signal currents were causing electrostriction or anything like that.
Presumably, I could avoid the problem by suspending the cable in a way that isolated it from any possible vibration. Or I could chuck the cable and put in one that isn't vibration sensitive. The latter strikes me as the easier approach.
The vibration I referred to was external mechanical vibration being transduced by the coax. Music tends to rattle things around. I seriously doubt that the microamp signal currents were causing electrostriction or anything like that.
Keithley makes a triax for femto-amp/nano-volt measurements (truely beautiful looking stuff). I'm surprised no one had tried it or repackaged it for audio.
Motion isn't required to build up a charge on floating conductors. A couple years back I kept myself entertained at the base of a 200 foot floating AM tower under inspection by rubbing a piece of broken cable clamp on the end of a long stick across the tower base. There was enough induced potential from nearby towers to cause the metal to literally burst into flames at the contact point. It's a lesson quickly learned by anyone who's taken a hit from a floating tower.
Another example, when playing with solid EMT steel speaker cabinets I found that, left floating, they built up a healthy charge just sitting on stands. Got zapped a few times.
Scott, there have been a few triax audio cables. I use one at home distributed by a manufacturer of musical instrument cables for studios, Zaolla. Discovered it was triax when replacing the RCA connectors.
Another example, when playing with solid EMT steel speaker cabinets I found that, left floating, they built up a healthy charge just sitting on stands. Got zapped a few times.
Scott, there have been a few triax audio cables. I use one at home distributed by a manufacturer of musical instrument cables for studios, Zaolla. Discovered it was triax when replacing the RCA connectors.
I guess the next obvious question is: Where do microphonics come into play? Did you get the same effect as rapping on a charged capacitor?
John
Thanks Scott.
Sounds as though sliding the neutral cotton onto the Nylon coated Litz, with some of the polyethylene material pre-attached, would impart a negative charge to the entire cable.
Since there is no ground drain to these things, they could only be brought to neutral by the electrostatic moments in the signal, hence "burn in". Does this make sense to you?
Bud
Sounds as though sliding the neutral cotton onto the Nylon coated Litz, with some of the polyethylene material pre-attached, would impart a negative charge to the entire cable.
Since there is no ground drain to these things, they could only be brought to neutral by the electrostatic moments in the signal, hence "burn in". Does this make sense to you?
Bud
But isn't this more a problem with a lot of cable makers? That they don't do anything about transfer impedance - there cables are actually broken.
I have only observed this kind of "burn in" when all impedances were 10^12 Ohms. Charges trapped on Teflon will eventually yield to cosmic rays if nothing else.
Yeah none of this stuff works on me. Of course when I go back and think about what I have done with my cables I usually test them just to be sure they aren't broken. So maybe I broke all of my cables in that way. With chirp tests and the sweeps in 192 I would assume it's actually a little better then that product. But also shouldn't this be some how testable - aaaah see it's like Heisenberg as soon as you hit it with a test tone it gets burned in so you can't measure it. I see.
How about this. We take a rip of a CD and run it through the unbroken in cables in a loopback recording to 44.1 - 16-bit. We then move the cables to another soundcard and run a break in session on the cables. We run squarewav sweeps up to the highest frequency that soundcard will emit. Then we move the cables back to the previous soundcard and record the same song. Then you must verify that you can actually hear a difference between the two recordings with ABX testing.
How about this. We take a rip of a CD and run it through the unbroken in cables in a loopback recording to 44.1 - 16-bit. We then move the cables to another soundcard and run a break in session on the cables. We run squarewav sweeps up to the highest frequency that soundcard will emit. Then we move the cables back to the previous soundcard and record the same song. Then you must verify that you can actually hear a difference between the two recordings with ABX testing.
Scott,
What I have observed is the same pattern as I observe with output and IT transformers, just a much shorter period of sonic weirdness, two hours rather than 40.
Bud
What I have observed is the same pattern as I observe with output and IT transformers, just a much shorter period of sonic weirdness, two hours rather than 40.
Bud
Member
Joined 2002
Hi,
Time will tell that your guess is as good as mine.
Time will also tell you that timing is the essence of anything music
I bow,😉
Time will tell that your guess is as good as mine.
Time will also tell you that timing is the essence of anything music
I bow,😉
Hi,
If and when you'd get the chance to discuss scientific stuff with Russian internautes you'll find them so clever it will pale our little notion of what can and can't be into triviality.
Believe and trust your senses is all I can say. One day maybe?
Cheers, 😉
analog_sa said:
If and when you'd get the chance to discuss scientific stuff with Russian internautes you'll find them so clever it will pale our little notion of what can and can't be into triviality.
Believe and trust your senses is all I can say. One day maybe?
Cheers, 😉
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