Came across mic/guitar lead handling noise a few times. You get pops and crackles if you step on or bend them.
Not good for live events but it only ever happened with really dirt cheap leads.
Not good for live events but it only ever happened with really dirt cheap leads.
Yes, Keithley makes special low noise triax for electrometer applications where the discharge times involve up to 10^17 Ohms. The also use solid sapphire insulators in places. I don't think the bulk resistivity of PVC cuts it, I caught a tech trying to measure a 300fA input current with a cheap 1 meter BNC cable which I demonstrated had 60Meg parallel resistance.
Your implication was that this was a steady state current since you estimated that although small, that it was always there in the system. A building potential does not imply that a current exists. There is no current flowing in the air during a thunderstorm until it discharges in a short period of time in the form of lightning. In both that case and in this case, some other force is causing the electric potential to build.
Did I? All I said was that if a certain current flowed then a certain voltage would be developed across the source impedance. I said nothing about its temporal properties.lemans23 said:
If charge is being moved (in order to build up a potential) then by definition there is a current. Charge conservation (a law of nature) absolutely insists on this. Huge currents flow in a thundercloud as it builds up to the even bigger current of a lightning stroke.
Electrostatic charges involve a current to build up the charge and then a current in the opposite direction to perform the discharge. Which is more audible depends on timing and magnitudes, but there are two currents.
To clarify, the triboelectric effects, which is what it seems to be, that I hear don't manifest as pops and crackles - that sort of thing would make the whole business of sorting things very easy, if it was that obvious - rather, it's a general degradation, 'veiling' of the sound - it's as if in some subtle way the operating point of some part of the overall system is altered, sufficently to have it perform well below par ...
A simplistic analogy is to get a master reel to reel tape, and produce, say, a 10th generation copy of it on normal professional gear. Listening to the latter, in isolation, nothing would be obviously 'wrong' - but if you then listened to the original master, it would be "Oh, dear ... "
That's the sort of SQ impact that we're dealing with ...
A simplistic analogy is to get a master reel to reel tape, and produce, say, a 10th generation copy of it on normal professional gear. Listening to the latter, in isolation, nothing would be obviously 'wrong' - but if you then listened to the original master, it would be "Oh, dear ... "
That's the sort of SQ impact that we're dealing with ...
I see that you enjoy semantical reasoning rather than keeping it simple to have a proper discussion, so I will agree to disagree with your statements. If you understand electronics which you clearly do, you would absolutely understand why I took objection to your statement. Your assertion is false.
Current is the flow of electric charge, not simply moving charges about. The word flow there is key, as it requires a conductive medium transporting electrons or ions. It simply depends on the field potential if you can use something as a conductor. Charges building on the surface of something is not electric current. Them discharging and flowing to a conductive termination is.
By your argument, current is constantly flowing everywhere regardless of the medium because charges are constantly moving. You absolutely know why this is incredibly misleading to someone who does not have a background in electronics or engineering.
Last edited:
I do not see at all how the movement of net charge from one place to another is not current.
I did not say that it wasn't. I said that simply the movement of charges is not electric current. By definition, it requires a flow of charged particles. This is a very specific concept. I will do my best. 🙂
Current can be defined in a number of ways, but the root of the definition is charge flowing through a surface. You can represent this by the integration of the scalar product of current density J and cross sectional area A: int(J . dA). Both J and A are vector quantities as they are describing the flow of particles in a certain direction. dA is simply therefore a differential area vector. J is the product of sigma * E, where sigma is the conductivity of the medium and E is the electric field vector. If you have charges flying about in all directions, then you must specify the electric field acting on each of those charges passing through a specified surface to consider that a current. If you wish to consider a charged particle's motion current, then that is fine assuming you define it as such. The movement of a charge, however, does not define current.
Perhaps this works best, since many physics students and starting EEs learn it as such: current is analogous to water flowing in a pipe. This analogy works because said pipe has a specified cross section, the molecules are all being acted on by the same net force (the water pressure multiplied by the pipe area), and are constituting a continuous flow. You would never say that water droplets flying around in say a mist or overspray from a fountain are flowing anywhere. Their motion is not random, but it is not a current of water. The same applies here. Charges can move about wherever they please, but charges moving from one place to another in an undefined manner is not a current.
I think that is enough silly discussion on definitions, I say we return to the topic of speaker cables. 🙂
As I commented previously a cable with silver conductor and PTFE insulation needs a minimum of 200 hour, but possibly closer to 1000 hour before it performs optimal when electrically connected and not moved.
If the said cable are disconnected and moved it needs a new period of time before performing.
The triboelectric effect may be a part of this.
When connecting a silver/PTFE cable it sounds "horrible" the first 30 minutes and then sounds better as time passes..
When connecting a copper/PVC cable it sounds maybe close its best from the start and then "degrades" as time passes - well I do not think it really "degrades", but the SQ does not improve as it settles..
Due to this I find it completely nonsense to perform a "normal" DBT.
Also in regard of amplifiers, speakers, main filters etc. there are issues that involve time factors.
And thus I find a "normal" DBT useless also in this respect.
I have experimented a lot with "blind testing" and the concept does not work due to the above mentioned issues and it does not work due to how our senses and brain works.
However to evaluate if and what differences a USB cable (as an example) may give I use two completely identical setups (except the cables in question) and let both setups play the same source material (from RAM) a minimum of two weeks before comparing.
When comparing it is then easy to hear clear differences.
But it is also very easy to arrange the comparison so the brain get confused..
My DAC have both IIR and FIR filters and those have different settings and can also be completely turned off. As the DAC have a remote control and display I programmed a random generator that selects a random IIR and FIR filter settings every time I push a button on the remote control.
With the display turned off I then push the random button and listens and can for sure hear differences.
The greatest fun with this function are to test it on visitors and let them try to find a best sounding combination and then turn on the display and "see" the active settings.
Even if I program a round robin routine that goes through a defined sequence of the filter settings it is extremely difficult for visitors to select a best sounding setting as they have to step through the whole sequence before they are back to the "previous" setting and the brain gets confused.
If you move a charge, J.dA (sorry, I don't have vector symbols on this keyboard) is not zero, i.e., there's current, unless there's a net movement of equal charge in the other direction through that surface element.
Pure nonsense.lemans23 said:
Any moving charge by definition is a current, however it is moving. Electrons moving in a wire is a current. Charged raindrops rising convectively in a cloud is a current. Moving charge apart after rubbing a cat with a glass bottle is a current. It really is that simple. Confusion arises in people who wrongly believe that only the first example is a real current.
This is not 'semantical reasoning'. It is simple first-year physics. I can't agree to differ as it is simply a matter of me being right and you being wrong. This is not a matter of opinion!
It is!! Have you heard of electric charge conservation? Any change in local charge density must be balanced by a flux of current. Any change, not just organised changes.
Last edited:
😀
Test it yourself and you will know.
Due to I repatedly and many others also experienced this issue I have started to use silk as insulation, and for the record also gold as conductors.
And yes I know that gold have a higher resistance than copper and silver.
It is other properties that results in a lower noise level that makes a difference.
As gold is expensive I have started the evaluation of other materials that have a much lower cost than gold and hope the results enables me to sell the gold and spend the money on something other.
After Scott's picture can we conclude that the problem with teflon might not be entirely due to triboelectricity but also piezoelectricity? Still a good reason not to use it anywhere near an audio signal!
The following three - DF96, marce and SY - should order enough popcorn 😀
Quite funny to follow this threesomes postings...
- Status
- Not open for further replies.