Facts wanted on interconnects

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u235

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Hi

I am in the process of gradually improving my system by acquisition of 2nd hand stuff, moving things around, trying to understand the technology, etc. I'm in computers with a software background, but poor at electronics. I started off trying to understand speakers a bit better (it all makes sense, but very arcane and tough for me to follow the maths) and I thought I'd tackle something really simple - cables. Interconnects first.

So it's impedance and capacitance (innit?)

According to my calculations, a co-axial cable with a 1mm diameter core and a shield at 1mm radius (ie 2mm diameter) should have a capacitance of about 60 picofarads per metre. This agrees at a sort of order-of-magnitude level with what I've read. If I increase the cable thickness to 4mm (about the same as TV coax) then the capacitance goes down to 38picofarads per metre. So that would seem a good cheap way of achieving an improvement, if a difference of 22picofarads in my interconnects is relevant. So how to find that out? I'm of the school that feels if it's not there, you can't hear it.

The only decent, understandable facts I can find on signal attenuation or interference based on capacitance are at MHz frequencies, here:  http://www.littelfuse.com/data/en/Application_Notes/ec624.pdf.

So although they show very little interference at 10 picofarads, the problem is:
a) The voltages. What is the voltage range in an interconnect?
b) The frequencies. There is a perceptible difference when the frequency is multiplied by 20 (from 12MHz to 240MHz), but obviously one can't extrapolate to KHz
c) Capacitance. The difference between 10picofarads and 550 picofarads at 12Mhz is huge. Where would 60picofarads sit?
d) Materials. Nothing in my limited research provides factual support that capacitance in a cable is affected by the materials it's made of, although there are masses of sales bumf and subjective warblings . Reference here: en.wikipedia.org/wiki/Capacitance#Stray_capacitance

So my data, although interesting, is not relevant. So I'm looking for better data, where at least one of frequency and voltage is more within listening range(Not surmise, experience or conjecture - there is bags of that available!)

Anyone interested? I want to start on speaker cables next.

Oh, one other thing - I'm assuming that impedence in 1m of interconnect is irrelevant. I measured 100m of telephone wire on a roll- 5 ohms!
 
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