That's the fashion part. But hey, lower DA, so it will not pollute DC measurements.
This thread is blessed with an abundance of very smart people from many disciplines, it is enjoyable having discussions here as I enjoy learning from them all.
Good luck with the phono preamps..
j
I used Teflon over bus wire extensively, primarily because there is very little meltback when soldering (and if there is any one had best reduce the soldering temperature and have some good fume hood going, as there's a higher vapor pressure than you want of toxic stuff). One of my supporters in the department joked that I was the only person he knew who made his own wire.
On the piezoelectric and triboelectric front, I'm surprised no one commented on the cables out there with battery packs. If the source impedance is sufficiently high I can confirm that they do have significant signal generation capability. I was inclined when hearing about them that it was one of the silliest notions yet. But in the fledgling amp company one guy had a special cushy relationship with the cable company head, and got "great deals" on sets of them, which then naturally had to be used in the show demos. It was amusing to me to see these little class D boards making a transition to these anaconda-sized speaker cables with battery packs.
The system did sound pretty good though. The noise floor was entirely due to the Bel Canto DAC, which was supposedly one of the quieter ones.
On the piezoelectric and triboelectric front, I'm surprised no one commented on the cables out there with battery packs. If the source impedance is sufficiently high I can confirm that they do have significant signal generation capability. I was inclined when hearing about them that it was one of the silliest notions yet. But in the fledgling amp company one guy had a special cushy relationship with the cable company head, and got "great deals" on sets of them, which then naturally had to be used in the show demos. It was amusing to me to see these little class D boards making a transition to these anaconda-sized speaker cables with battery packs.
The system did sound pretty good though. The noise floor was entirely due to the Bel Canto DAC, which was supposedly one of the quieter ones.
Shunpiker (That is where the term "piker" comes from. Local folks would have a short cut road just before the toll booth so they could bypass or shun the toll collector.)
The now outdated TV distribution in a stadium would require 1 GHz at millivolt levels, ingress and all those other nasty issues. Typical would be 500-750 drops for just TV. That doesn't include the actual distribution to the individual drop directional couplers. Then there would be the low bandwidth (100 MHz.) stuff for the TV cameras to use, another 300 to 500 cables.
I used to have the same talk with the electrical crew installing things. The good crews would get the message and end up rewiring their home's CATV systems.
For all the crews I would let them pull a few cables, then TDR them and point to where they bent or otherwise did not follow the rules. They knew where they did it and were quite surprised to find out I knew.
These days all the stadiums use CAT5 for the TV distribution as data. That gives at least a 15 second delay from live to what is on the TV. (Camera to truck to satellite uplink, down to network, back up and down to special effects house, back up and down to network distribution to local station and then adding compression and decompression time!)
By the way as the video is adaptively compressed the time required depends on the motion in the image. Since the audio is not an adaptive process there is now loss of lip sync that hasn't been seen since the first "Talkies!"
I actually have lost count of how many stadiums I have wired in my career!
John (N) it is a shame we agree on so much, kind of takes the fun out of it!
I haven't. Zero...for me.
John (N) it is a shame we agree on so much, kind of takes the fun out of it!
Well...lets put some fun back in..
Your ugly.
j
See we agree again! That is why there are no pictures of me on any of the articles I have written!
I too, remain shy of the camera. But of course, not because I'm ugly...
bcarso...i thought you were gonna say wrap as in, half the shield on one side of the nail, half on the other..
j
I think that a few points about the ST1700 and Sound Technology in general, that gives me perhaps a better understanding of what the ST1700 series is, and how it compares, in what I have found, to the AP products.
First, I have some knowledge of Sound Technology, the company, and a great deal of experience in using it for a number of measurements. I got my first personal unit in 1976, and it was then pretty impressive, and used it for about 20 years on an almost daily basis.
This design was really a 'copy' of the HP339, with a few additions, and perhaps a few 'shortcuts' that make the HP339, perhaps a better choice as a USED piece of test equipment. I have used both, interchangeably, but recently, one of my colleagues politely rejected the purchase of an ST1710 for an HP339. I can't blame him, as these instruments, when they get really old, get problematic, and 'fussy'. I have 4 of them in my lab, at this time, and they are each a headache to keep operating happily. It is almost like certain parts choices were taken, without thinking ahead 25-35 years, and these become a consistent annoyance as the unit significantly ages. This makes repeating with any consistency, what I originally measured 10-15 years ago, and show it as 'hard data' almost impossible. Yet the harmonics continue to be measurable, but ONLY on certain cables. Sometimes these cables are REALLY expensive, sometimes, they are relatively cheap. In any case, virtually everything that I tried to remove these harmonics from appearing with these specific 'bad' cables has failed, so far, except perhaps by the approach made by Audio Precision which has a number of changes, as well as a number of similarities. The AP has a significantly lower distortion notch, somewhat lower distortion audio oscillator, and slightly lower input noise level. Each of these improvements, while commendable, should not stop me from measuring wire differences, in fact it should make it easier to see and measure these differences. So what went wrong? Is there a hidden 'ground loop' like JN maintains? Perhaps, but I think it is the TRANSFORMER ISOLATED balanced drive circuit that really makes the difference. It is the only SIGNIFICANT difference between the two measurement approaches that I can find.
Now, let's say JN is correct in presuming it is a very low level ground loop that appears to have a 'dead zone' that causes all the harmonic distortion. It would have to be something like crossover distortion, because the distortion RISES with lower input levels. Now, what do we do? Make a fully balanced transformer isolated drive? That might work to remove the distortion products, but what about a NORMAL audio playback system? Would not each and every piece of audio equipment, even made to a professional level, have this problem appear with these specific 'bad' wires or perhaps another set of wires? What then? Should we NOT find out WHY two seemingly similar wires, both with 75 ohm characteristic impedance, soldered hot leads to the center pins, both 1M long, and seemingly negligible DC resistance in either the hot lead or the shield return measure significantly differently, especially at low levels? Less than 100mV (you know, 0.1W to 10W from the output of the power amp (given THX gain settings).
It would seem that would be important, it is to me, at least. What if the AP is MISSING SOMETHING that is REAL in the 'real world', and is only seen as an artifact in the 'measurement world'?
I realize some very 'hi minded' speculations have come up, but WHY then are these secondary effects not significantly reduced or removed when significantly different frequencies are used, as well as significantly different drive and load resistances?
Until I have specific evidence that there is something so wrong with my test equipment that it is next to useless, I will continue to use it.
Those who criticize me, should get an AP or and ST or an HP339, and get some REAL experience with the measurement process, before speculating as to what is wrong with my approach.
First, I have some knowledge of Sound Technology, the company, and a great deal of experience in using it for a number of measurements. I got my first personal unit in 1976, and it was then pretty impressive, and used it for about 20 years on an almost daily basis.
This design was really a 'copy' of the HP339, with a few additions, and perhaps a few 'shortcuts' that make the HP339, perhaps a better choice as a USED piece of test equipment. I have used both, interchangeably, but recently, one of my colleagues politely rejected the purchase of an ST1710 for an HP339. I can't blame him, as these instruments, when they get really old, get problematic, and 'fussy'. I have 4 of them in my lab, at this time, and they are each a headache to keep operating happily. It is almost like certain parts choices were taken, without thinking ahead 25-35 years, and these become a consistent annoyance as the unit significantly ages. This makes repeating with any consistency, what I originally measured 10-15 years ago, and show it as 'hard data' almost impossible. Yet the harmonics continue to be measurable, but ONLY on certain cables. Sometimes these cables are REALLY expensive, sometimes, they are relatively cheap. In any case, virtually everything that I tried to remove these harmonics from appearing with these specific 'bad' cables has failed, so far, except perhaps by the approach made by Audio Precision which has a number of changes, as well as a number of similarities. The AP has a significantly lower distortion notch, somewhat lower distortion audio oscillator, and slightly lower input noise level. Each of these improvements, while commendable, should not stop me from measuring wire differences, in fact it should make it easier to see and measure these differences. So what went wrong? Is there a hidden 'ground loop' like JN maintains? Perhaps, but I think it is the TRANSFORMER ISOLATED balanced drive circuit that really makes the difference. It is the only SIGNIFICANT difference between the two measurement approaches that I can find.
Now, let's say JN is correct in presuming it is a very low level ground loop that appears to have a 'dead zone' that causes all the harmonic distortion. It would have to be something like crossover distortion, because the distortion RISES with lower input levels. Now, what do we do? Make a fully balanced transformer isolated drive? That might work to remove the distortion products, but what about a NORMAL audio playback system? Would not each and every piece of audio equipment, even made to a professional level, have this problem appear with these specific 'bad' wires or perhaps another set of wires? What then? Should we NOT find out WHY two seemingly similar wires, both with 75 ohm characteristic impedance, soldered hot leads to the center pins, both 1M long, and seemingly negligible DC resistance in either the hot lead or the shield return measure significantly differently, especially at low levels? Less than 100mV (you know, 0.1W to 10W from the output of the power amp (given THX gain settings).
It would seem that would be important, it is to me, at least. What if the AP is MISSING SOMETHING that is REAL in the 'real world', and is only seen as an artifact in the 'measurement world'?
I realize some very 'hi minded' speculations have come up, but WHY then are these secondary effects not significantly reduced or removed when significantly different frequencies are used, as well as significantly different drive and load resistances?
Until I have specific evidence that there is something so wrong with my test equipment that it is next to useless, I will continue to use it.
Those who criticize me, should get an AP or and ST or an HP339, and get some REAL experience with the measurement process, before speculating as to what is wrong with my approach.
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I suspect that could have happened, but the way most electricians conceive of cable is probably based on his/her experience with mains power, and therefore driving a nail through a cable would be seen as dangerous.I too, remain shy of the camera. But of course, not because I'm ugly...
bcarso...i thought you were gonna say wrap as in, half the shield on one side of the nail, half on the other..
j
I believe I did relate the story of the master electrician who didn't know the difference between a series and a parallel circuit, and wired all the magnetic switches on doors in parallel for a security system, an expensive mistake for which the electrical contracting company tried to get me to pay. I was foolish enough not to check the work as it was being done, but otherwise clear on the specification. One lives and (sometimes) learns.
There is a big hint there in the fact that AP doesn't have the problem.
THIS is precisely where you have gone off the track.
I have never said that a ground loop appears to have a dead zone..where did you come up with that???
I have stated from day 1, your setup has a ground loop that diverts the harmonics either to the input section, or away from the input section, based on the break frequency of the ground loop.
Read IEEE-STD-1050. That would be a good start for you.
Your equipment is reacting to the integrity of the ground. There are red flags all over your results which show that.
You continue to make the flawed assertion that the wire is generating the distortion. It is not. It is a bad setup. The setup is causing the distortion. Edit: And, at the pro level, whitlock is making progress in general, but has yet to address the overall EMC issue..
As to your question regarding a normal audio system? Simple, design the equipment such that it is not sensitive to ground loop currents across the audio bandwidth.
I provided the schematic for that test.
What if pigs can fly?? Fix your test setup. You have basic flaws in it.
You are welcome to do as you wish, as long as you don't try to re-write physics with unsupported theories..your tests are of value despite your incorrect conclusions.
THAT HAS BEEN DONE, John. You ignored the results.
j
ps..who has been criticizing you? On this thread?
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John (N)
In my playing around I have found in two cases (A very small percentage!) where there appears to be diode action at very low levels on a mechanical contact.
Now knowing how Galena lead crystals were prized in their day for making AM receivers, it was not a great surprise that such action could occur on some random contact.
So I think there actually may be a real explanation for some UFO sightings!
ES
P.S. I use battery power supplies for all the low level stuff!
In my playing around I have found in two cases (A very small percentage!) where there appears to be diode action at very low levels on a mechanical contact.
Now knowing how Galena lead crystals were prized in their day for making AM receivers, it was not a great surprise that such action could occur on some random contact.
So I think there actually may be a real explanation for some UFO sightings!
ES
P.S. I use battery power supplies for all the low level stuff!
I have to admit, this is the same reason why I prefer teflon insulated wires. However people who design by SIMMing do not know this secret and think that my equipment sounds so nice partially because of some magic properties of wires, while they are simply convinient for prototyping using soldering iron.
Teflon runs like Silly Putty under pressure. So how would that work. Also, molten solder and silver at the right temperature REALLY love each other. It will suck through the capillairies between the wires anyways.
I think the problem might be more with the teflon coax silver on copper on steel wire. Steel can withstand repetitive bending much worse than copper.
vac
It worked well not only in my prototypes, but also in all Soviet military equipment that used teflon wire MGTF.
This one:
An externally hosted image should be here but it was not working when we last tested it.
You are very good.
In the decade of trying to get JC to start this thinking process, you are the first to actually begin to get it. I had hoped he would first, but such is life..
IEEE-STD-1050 details this in a fashion, but requires understanding to arrive at the conclusions.....
Darn, this computer is shutting down in 3 minutes...sigh..
The shield current counters the core current. If the shield current is exactly equal and opposite the core current, there is no problem. And, no field.
The shield resistivity, it's total loop resistance, and any non linearities in the shield to ground connection, determine the quality and quantity of the shield current when a ground loop has been formed.
The problem is, how to make the system impervious to that ground loop current.
ttfn
jn
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