 
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
|
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
73.19.55.31
In Reply to: RE: Dielectric constant for a DC cable posted by 13th Duke of Wymbourne on February 24, 2020 at 16:48:33
Perhaps evaluating a DC umbilical featuring insulation with a low dielectric constant would change your mind about the effects of a poor dielectric material such as typical PVC vs. cellular/foamed FEP at the top of the list, solid FEP and PTFE, then polyethylene and polypropylene, with PVC at the bottom of the list. A signal cable with a low dielectric constant insulator may be more significant, but the influence of a high-performance DC umbilical provides the same type of sonic betterment as that of a signal cable, AC power cord, or any other cable that is an integral part of the signal path. So when I'm told something that I have direct experience of is somehow not significant, I beg to differ based on my own direct experience of the matter. One should have direct experience of a topic before claiming actual insights about the audible influence of a particular type of audio device in this forum.
Follow Ups:
As ever, I am not questioning your experiences. There is nothing wrong with a quest to lower dielectric constant but if it adds to system cost then a DC cable is not the place assign those funds. All dielectric constant tells you is how much more capacitance there will be per unit volume of a dielectric compared to air, so it is a measure of quantity of capacitance not quality of capacitance. A DC supply will undoubtedly have a ton of electrolytic capacitance between the +ve and -ve wires so a tiny fraction more capacitance in the umbilical will be of no consequence.
Low dielectric constant can be important at RF where capacitive signal loss in the cable is significant. W.L. Gore make expensive RF cables with foamed teflon dielectric for just this application (I beleieve this is the same/similar material to Gore-Tex but I don't know if they invented it first for outdoor wear or for RF cables and later found the other use). So, low dielectric loss is good for RF cables and this seems to have been leveraged that it must then also be good for audio cables. Some audio cable manufacturers have taken this to the extreme in aspiring to have only air as the dielectric material close to their conductors (e.g. Nordost)
Regards,
13DoW
Quality of capacitance not just quantity of capacitance, meaning how the effect of that capacitance actually sounds based on the dielectric involvement of energy absorption and energy release is at the heart of audiophile cabling, not just the conductive metallurgy and geometry of a cable. How a cable actually works tends to be misunderstood, and often taken for granted that as long as a cable passes signal, and/or provides adequate current demand with minimal voltage drop, it's as good as it gets. I'm quite aware of Gore ePTFE cables for RF purposes, and how that accidental innovation has influenced audiophile cable makers to implement the lowest possible dielectric involvement based on achieving optimum transparency, with the least coloration caused by a plastic insulator which can greatly affect the transmission of energy, getting in the way of what the conductive element is trying to convey to the listener.
Dielectric absorption in capacitors is a known problem that must be present in cables using the same dielectric materials but to what degree I don't know. If you have any good references, particularly a table of dielectric absorption I would be interested to know if there is a correlation between dielectric constant and dielectric absorption. Dielectric constant is defined as a resistive loss, i.e. no memory effect though I did find a reference to relative permativitty having a memory effect but it wasn't clear to me it was the same thing as the hysteresis effect of dieletric absorption?
My inner pedant takes a small exception to your statement that there is more to a cable than passing a signal. This cannot be true but I trust you really mean the degree to which it passes the signal. Then we end up at the thorny topic of how small an imperfection is significant but not today :). Though further pedantry does force me restate my original point that if there is no change in voltage across a dielectric (i.e. DC) then this all moot.
Regards,
13DoW
What I meant by just passing signal is that program material is successfully transmitted from source to load, regardless of sound quality. A 69 cent stereo patch cable will pass signal, but even you will agree that a more competent cable of your choice, perhaps a pro audio product will provide a better sounding portrayal of music vs. that of a poor performer.
The price of VH Audio's V-Quad Cu21 is $26.99 per foot. I only require 2 feet for most DIY DC umbilical builds. The price of an Oyaide DC-2.1G DC plug is $20. I tend to only require one DC plug placed at the load end.
$26.99 X 2 = $53.98 + $20 = $73.98 plus some more coin for 2 feet of Techflex Clean Cut sleeving. That cost-level is much less than a pair of high-performance audiophile interconnects, a high-performance audiophile AC power cord, and many high-end capacitors for that matter. If that figure seems like too much to spend, nobody is twisting folks arms to pull the trigger on parts to build a state of the art audiophile DC umbilical.
I am in the process of building a 10 conductor DC power supply cable. The connector is dictated by the manufacturer and the only choice is silver or gold plated pins.
I am inclined to stay with silver as the device has the silver pin sockets.
The wire is where I am stuck. The pins are limited to 18AWG. I wanted to go with a PTFE pure copper wire. I was then going to attempt some kind of crazy 10 wire braid or twist and put in a.....well no idea. I can't seem to find a real high quality 10 conductor wire.
My current pick is the 19AWG Kimber TCSS wire.
https://www.thecableco.com/diy-cables-and-connectors/tcss-bulk-single-conductor-bulk-hook-up-wire.html
What length DC umbilical are you going to build, and what is your target budget-level?
It is only going to be 18" or so. There is no budget. I am willing to spend what i need to, its going on an expensive piece of gear.
VH Audio 21 AWG UniCrystal OCC Copper Hookup Wire with AirLok Insulation is excellent for use as a low to medium current DIY DC umbilical build. Label each conductor at both ends, solder the wires to the corresponding terminals, then gently twist the conductors just enough to accomplish a lazy twist so the wiring can have a usable bend radius, which might require a bit longer length than only 18 inches for the solid core wires. However, the cellular/foamed FEP Teflon insulation makes the solid core wire easier to bend than a solid insulation. Use thin heat shrink to hold the wires together, then cover with Techflex braided sleeving for protection.
See link:
Thanks. I will check that out. any reason to choose the 21 AWG over the 18 AWG?
21 AWG solid core wire is much more manageable for a 10-conductor cable assembly than 18 AWG solid core wire with twice the cross section. The key issue to consider is potential voltage drop due to gauge and length, of which 21 AWG when 3 feet long or less will be the most advisable 1.5 percent or less voltage drop for a low-current 5V DC umbilical application, for example. Do you know the rated voltage and current draw involved with all 10 conductors?
This is what I got back from the Manufacturer:
Pin 1, 3, 7 are +12V.
Pin 5, 9 are -12V.
The rest are GND.
Pin 1, 2 are rated for 1.5A
The 21 AWG AirLok hookup wire would be perfect for that application. Can you upload a photo or indicate the make/model of the DC connector? Is it the same type of connector at both ends?
I suggest building the DC umbilical with 2 foot wires, which will shorten a bit after they are gently twisted together with a lazy twist rate to form a bundle with a usable bend radius.
It's a hirose rm-w.
https://www.hirose.com/product/download/?distributor=mouser&type=catalogue&lang=en&num=RM15WTPZ-10P(71)
Make sure to add more heat shrink for strain relief where the wiring is secured to the connector.
Just ordered the wire. I will wait to it comes to order the connectors as I am not sure what size cable clamp to buy. I need to see what the diameter of the 10 wires and some shrink tubing come out to.
I appreciate all the advise.
Ask myself or Chris of VH Audio for any further advice. Maybe Chris can estimate the diameter of the 10-conductor bundle, and a particular size/type of heat shrink to choose. I recommend the Techflex Clean Cut braided sleeving he carries, since it is easy to work with, and provides excellent protection for the purpose.
Ok. Chatted back and forth with Chris a little and ordered everything up. I will report back when it showed up. Mouser is not always the quickest getting to me.
I'll keep an eye out for the report.
Cheers, Duster
| FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
||||||||||||||
This post is made possible by the generous support of people like you and our sponsors:
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2025, Audio Asylum, all rights reserved ]
