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Dielectrics and such...??

Knowing a little about something can be dangerous! Having read about poor dielectric designs, static fields, EMI…etc., I don’t know if my idea of executing some shotgun runs of speaker cables is a good or bad idea….

I want to use double shotgun runs of Kimber 4tc per speaker. Rather than twist the runs together, I want to try keeping them separated at equal width throughout the runs. My thought is to “laminate” four equal lengths of the cables together with some type of clear tape (i.e.: separate and secure four lengths of cables by an equal and consistent width throughout the run – say one-inch - by “sandwiching” all four cable between heavy clear tape).

Question: will the tape itself hinder the dialectic properties of the cables (because I assume the tape is a poor dielectric)…??

What say you electrical engineer types?

Thank you.

_Ben
2chnlben
almarg's avatar
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almarg
9,670 posts
 
Hi Kijanki,

I suspect that you are basing those calculations on typical numbers for two conductors that are not twisted. See the link in my previous post, though, which shows a photo and the specs of the specific cable. And note that the inductance number is for 2.5 meters.

So due to the braided and twisted construction of the cable, it appears that the inductance is only about 87 nH per foot-run, for a single cable. A double-shotgun configuration (four two-conductor cables in parallel for each speaker) would reduce that to about 22 nH per foot-run, which of course is extremely low.

Best regards,
-- Al
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kijanki
4,432 posts
 
Al, I didn't notice the link you provided. I agree that 22nH per foot would be extremely low and we can take it out of the equation. So what else is there (other than resistance, inductance or dielectric) to consider?
almarg's avatar
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almarg
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So what else is there (other than resistance, inductance or dielectric) to consider?
Nothing else that I can think of, beyond what we've already said. I don't think that dielectric absorption will be an issue. The electric field between adjacent paralleled cables will be minimal, partly because of the one-inch distance, and partly because of the cancellation resulting from the twisted and braided construction of the two conductors in each of the four paralleled cables. Also, depending on which of the two physical configurations I asked about is used, the dielectric between paralleled cables may be mostly air, which as I understand it has essentially no susceptibility to dielectric absorption.

Total capacitance (between + and -) for a 2.5 meter run (about 8.2 feet) would be 1448 pf, somewhat on the high side but I suspect still low enough to not have audible consequences with the great majority of amplifiers.

Best regards,
-- Al
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kijanki
4,432 posts
 
Al, that's perhaps why some manufacturers use foam Teflon (including my Acoustic Zen Absolute ICs) - not only to lower dielectric constant but to reduce absorption (introducing air). As for driving 1.5nF - I'll take your word, having limited experience.
jbuenech
37 posts
 
Hi Ben, here is my experience. I have Kimber 3033 and tried to protect them from dust by wrapping them up in a thin plastic sheet, those used to keep food in the fridge.

Result was a huge change in sound for the worst. Harsh, unmusical,..., forcing me to remove it. Once done, good sound returned.

I admit I covered the whole lenght of the cables with the plastic sheet. Maybe using a short lenght of tape might not have the same effect.

Good luck.

Chema
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