All the small diameter mass produced cheap interconnects will tend to have high capacitance, because of the closeness of the inner and outer conductors except where the screen doesn't have 100% cover. If it's only 50%, then the capacitance is halved compared to one that is 100% covered. Those leads belong in a bin, not a hifi.
Of course if there is only 50% cover the screening will be very poor and the lead will potentially pick up a lot of interference, especially if used for low signal levels like phono. Small diameters and sparse screens = less copper = lower price. Fatter cheap cables usually just have thicker plastics sheaths. Some have a metalised mylar screen which gives 100% cover but also makes them tend to be microphonic, so no good for phono unless well made, then not cheap.
Of course if there is only 50% cover the screening will be very poor and the lead will potentially pick up a lot of interference, especially if used for low signal levels like phono. Small diameters and sparse screens = less copper = lower price. Fatter cheap cables usually just have thicker plastics sheaths. Some have a metalised mylar screen which gives 100% cover but also makes them tend to be microphonic, so no good for phono unless well made, then not cheap.
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Actually the cable with the highest O.D. had the highest capacitance. These aren't a "small diameter mass-produced cheap interconnect," but rather a "large diameter mass-produced cheap interconnect."
When it comes to shielding, 70% is typically all you need, you won't benefit much by going higher on a stationary cable:
https://www.mouser.com/pdfdocs/alphawire-Understanding-Shielded-Cable.pdf
"A braid is a woven mesh of bare or tinned copper wires. The braid provides a low-resistance path to ground and is much easier to termination by crimping or soldering when attaching a connector. But braided shields do not provide 100% coverage. They allow small gaps in coverage. Depending on the tightness of the weave, braids typically provide between 70% and 95% coverage. When the cable is stationary, 70% is usually sufficient. In fact, you won’t see an increase in shielding effectiveness with higher percentages of coverage. Because copper has higher conductivity than aluminum and the braid has more bulk for conducting noise, the braid is more effective as a shield. But it adds size and cost to the cable."
When it comes to shielding, 70% is typically all you need, you won't benefit much by going higher on a stationary cable:
https://www.mouser.com/pdfdocs/alphawire-Understanding-Shielded-Cable.pdf
"A braid is a woven mesh of bare or tinned copper wires. The braid provides a low-resistance path to ground and is much easier to termination by crimping or soldering when attaching a connector. But braided shields do not provide 100% coverage. They allow small gaps in coverage. Depending on the tightness of the weave, braids typically provide between 70% and 95% coverage. When the cable is stationary, 70% is usually sufficient. In fact, you won’t see an increase in shielding effectiveness with higher percentages of coverage. Because copper has higher conductivity than aluminum and the braid has more bulk for conducting noise, the braid is more effective as a shield. But it adds size and cost to the cable."
It was probably the only one with near 100% screen.
Thanks for the link, although the quote you posted is out of context to your application. Alpha Wire do not make cables for audio applications as far as I can see. The purpose of the cables subject of this technical note is discussed in the opening paragraph of the cited link. The signal to noise ratio requirement for audio is in the 100 to 100,000 times greater range (40-80dB) than the applications they are discussing.
Industrial control signals are typically in the range of volts with limited dynamic rage requirements, whereas phono signals are in the order of millivolts with a dynamic range requirement approaching 80dB. (SOTA for digital is >120dB dynamic range.) The noise floor for a phono cable is ideally in the range of 100s of nano-volts. In the context of phono level signals a household is an extremely noisey environment, for which Alpha says:
"For very noisy environments, multiple shielding layers are often used. Most common is using both a foil and a braid. In multiconductor cables, individual pairs are sometimes shielded with foil to provide crosstalk protection between the pairs, while the overall cable is shielded with foil, braid, or both. Cables also use two layers of foil or braid."
This is consistent with the past posts I have made.
It would probably be very good for an RJ45 socketed POE 100BASE-TX IP based phono cartridge that doesn't need to move because instead a servo moves the platter to keep the vinyl groove underneath the stylus.
Seriously, I wouldn't use tonearm cables for a LAN, and no one should think that LAN cables are a good idea for tonearm (or speaker cable FWIW).
We're talking sub-meter interconnects, not running great lengths of cabling through noisy communities or factories.
Indeed, the entire topic hinges on shielded vs. unshielded segments of phono cables, as in the Souther rewire you pictured with copious amounts of unshielded wiring to the arm. To talk of any need for double or triple shielded cabling for the rest of the .5 (or less) meter journey to the phono stages seems more than a bit incongruous.
Regardless, we're getting way off topic, I'd like this thread to be devoted to alternative methods to provide shielding of tonearm service loops.
What is incongruous is that you are conveniently ignoring that I described how I installed hidden grounded screening planes to deflect the EMI field around the exposed tonearm wiring, which placed the exposed conductors effectively inside a screened cage open on one side (the top). If I could have devised a method to make the perspex cover conductive the result would have been even better. The extremely low source impedance of the Koetsu MC cartridge mounted on the Souther tonearm does help as well.
Electronics and cartridge design have moved on a long way since the Souther was introduced more than 40 years ago, and so have people's expectations - in most cases. The owner was ecstatic with the huge improvement I achieved over the Souther's original noise performance. I personally would not be happy with the Souther setup because I know how far still it is from ideal. When I listen to records I want to hear what comes off the surface of the vinyl only, I do not want sizzle sauce, fries, or any other 'embellishment' on top, thank you vary much!
The only means to reducing the noise pickup of an unscreened cable is to have a differential (AKA balanced) phono preamplifier input. The allows any noise induced equally on the (+) and (-) conductors for each channel to be subtracted from the input and only the difference signal (the cartridge output) to be amplified. The point of twisting and/or braiding the conductors is to ensure that the noise voltage picked up is equal on each conductor so that it can be cancelled by a differential input. As soon as one conductor is shorted to ground by a single ended preamplifier circuit ~99.9% (60dB or more) of the benefit of the twisting or braiding is lost.
By design a phono cartridge is not a true balanced source, which by definition has two outputs which are referenced to ground and see-saw above and below it. However provided the cartridge manufacturer has not connected one of the channel (-) connections to the chassis of the cartridge, then a cartridge is a floating source, which means the noise induced in the tonearm cabling can be canceled by a differential input at the preamplifier. (Noise pickup up by the internal coils of the cartridge itself will not be canceled by a differential input, so resorting to hum-bucking may still be necessary as I gave an example of here: #29)
I introduced a simple method to evaluate without any tools just how much tonearm cabling is audibly degrading the noise floor of a turntable, way back in my first post in this thread here: #6. If you think a few centimetres of unshielded cable makes no difference, then you can't have tried the test or just don't care, or both. I have persisted and addressed each objection you posted for the benefit of all readers of the thread. I have explained relevant bits of the physics of cable screening in the context of turntables and shown why voodoo cable claims don't work. Hopefully other people will find this information useful if not yourself.
Double shielded LAN cable means foil and braid, and those are generally plated for long life.
Using the four inner conductors for stereo is possible, and this wire construction allows shielding of a very high quality.
Added attraction is ease of availability, and low price.
Using the four inner conductors for stereo is possible, and this wire construction allows shielding of a very high quality.
Added attraction is ease of availability, and low price.
The topic at hand is unique ways to shield tonearm service loops, and alternatives available for micro shielded cables. If you would like to share that other off-topic information, please do so in another thread.
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I have on occasion run into some internal wiring on various wireless devices that is extremely thin and flexible, but was used in fairly short lengths.
Similar thing could be said about some insanely tiny USB wiring I find sometimes inside some devices.
It is just that the lengths are typically so short, and they look purpose-made.
So the right idea but just need sources for at least .5-meter lengths.
This is sold in 100 yard lengths (rolls, bobbins, etc.) for use by the people who do data center cable work.
5 meters is easy to obtain. Or 0.5 meters...
5 meters is easy to obtain. Or 0.5 meters...
The standard ethernet cabling is too large for tonearm wiring. The wire I'm using now is #32, looking to stay there or find smaller.
A sample:
https://www.sab-cable.com/products/data-cables/dc-300-ds-tp.html
Search for "double shielded data cable"...
https://www.sab-cable.com/products/data-cables/dc-300-ds-tp.html
Search for "double shielded data cable"...
Every post of mine in this thread contains information specifically pertinent to the problem you have posed. You're welcome.
I'm done.
Another member pointed me in the right direction, thr gentleman that designed the exotic linear tonearm.
I'm outa here.
You're all hat and no cattle, John.
Another member pointed me in the right direction, thr gentleman that designed the exotic linear tonearm.
I'm outa here.
I've been rewiring tonearms for ~50 years starting with my father's Garrard Zero 100 quasi linear (articulated) tonearm which had significant amounts of exposed tonearm cable, back when I was studying tertiary electrical / electronic engineering.
The cool thing about physics is it works whether you believe in it or not. That applies equally to the solution you have found, and I'm sure many people would be pleased to know what that is, me included. I did see a reference to individual conductors screened by plating with no details posted. Apart from possibly high capacitance there's no reason why that might not be an improvement over what you have. Care to share?
BTW thank you for the personal feedback - it's invaluable. 🙂
The cool thing about physics is it works whether you believe in it or not. That applies equally to the solution you have found, and I'm sure many people would be pleased to know what that is, me included. I did see a reference to individual conductors screened by plating with no details posted. Apart from possibly high capacitance there's no reason why that might not be an improvement over what you have. Care to share?
BTW thank you for the personal feedback - it's invaluable. 🙂
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I realize that this is the OP's thread, but I for one have found your posts to be valuable johnmath. I don't find them to be off topic, but then again, I'm not the OP.
Thank you for your kind words Pars. Having been a professional electro-acoustic engineer for my entire career I'm actually pretty good at troubleshooting technical issues, just not ideological ones.
2 pair double shielded wire was 29 grams per meter, how will that affect the tone arm performance?
And a thicker wire will be a better conductor, apart from being easier to solder.
Cost? About a dollar a meter, if that.
It would be even cheaper to use the wire from a cell phone head set, the cheapest ones are 30 cents here! Thin too...
But sometimes it is like shouting at a deaf person, if their decision is made and they are looking for confirmation for the decision.
And a thicker wire will be a better conductor, apart from being easier to solder.
Cost? About a dollar a meter, if that.
It would be even cheaper to use the wire from a cell phone head set, the cheapest ones are 30 cents here! Thin too...
But sometimes it is like shouting at a deaf person, if their decision is made and they are looking for confirmation for the decision.