On 3/12/2020 10:03 pm, wrote:
Audio Interconnect cable Performance - is Return Wire Diameter a Factor?
**Not in the slightest. Impedance levels at line levels are such that
resistance is not an issue.
I was mucking around with interconnects and built a cable with an increased sized return wire. And i thought that this sounded better not worse than a similar cable without such a return wire.
**Humans are VERY easily fooled. You need to perform a proper double
blind test to verify. When you do, you will find that there is no
difference. Assuming, of course, that connectors are clean and tight.
What do i mean by better: the sound seemed fuller and had more weight.
This affect could be just an increased noise dimension, a genuine
improvement or technically no different but just sounds different. Not
wishing to accept this on its own i searched to find what might be
behind the effect and i came across the Eichmann Ratio„˘ this specifies
that the return pin of an RCA plug should be of a larger cross section
than the signal pin.
Eichmann states that "The Ratio forces the return conductor to respond rapidly to signals being transmitted through the signal conductor, at the same time providing a balance of reactance between signal and return. This ensures that all frequencies and their harmonics are transmitted in a more perfect state. The result is cleaner signal transfer. Which translates to better sound quality."
**Yeah, that's complete gobbledegook. Ignore it.
The Eichmann explanation might sound at first a bit doublespeak though this in itself does not invalidate the overall idea and of an impact. Eichmann limited their patent to just the interconnect plug connector. But the ideas effect on sound, if true, is likely to be so for the interconnect wire architecture as well. That is having a larger diameter return wire compared to the signal wire results in a so called better sound. one commentator on an interconnect cable that implemented a larger diameter return wire design also noted a better performance saying that €ś... the return signal is critical to the lower frequencies and he entrusts that to his special cable design€ť (http://6moons.com/audioreviews/johnblue6/jb4_4.html) - and if im reading this correctly the special feature design is a three wire return to a single wire signal.
Why? I suppose we need to consider the whole circuit. That is the signal starting from the source travels to the preamp then the power amp then the speakers then starts a return journey back to the source.
**BZZZTTT! Nope. That is not how an ALTERNATING signal works. Plus, the
whole thing operates at close to c (the speed of light).
any discontinuities to the electrical flow; like changes in wire, RCA
termination and connections will have an impedance effect and create
opportunities for reflections and noise.
**Well, yes, noise can be a problem with poor quality terminations.
Reflections happen because of impedance mismatches and will result in
noise and are an insertion loss.
**No. For all practical length audio cables (say: 1km) reflections are
simply not an issue. Impedance mismatches are not an issue in practical
systems, where source output Z 100 Ohms.
This is perhaps not so important in the case of the signal wire as the
low output resistance dovetails to a higher input resistance on its
journey between units.
**Which is the case with all sensibly designed systems. It is a trivial
exercise to design a source impedance of 10 Ohms.
however this is not true of the return €śback to the source€ť wire. and
as anything that impedes the current loop, including the return, will
impact on the whole circuit including the signal. So the return wire,
im thinking, is more susceptible to reflections. How large these
reflection are? i dont know, but having a larger diameter return wire
and larger contacts will lower impedance and hence result in a so called
better sound.
**There are no reflections. It is an AC signal.
Lots of people and manufacturers use coaxial cable as an interconnect cable wire and swear by the lower noise floor of these cables compared to similar grade/length twisted or untwisted versions. The coaxial cable return with its greater area compared to the signal wire will have less resistance. And maybe this has an impact on coaxial interconnect performance. The same argument is true for multi braided interconnects as these usually employ a greater number of strands for the return than for the signal.
this is only a hypothesis - or less: a drift in imagination... sandcastles - and im not so sure that the arguments stack up. there are other explanations. That is for the signal wire in an interconnect cable you might want to minimise capacitance while for the return wire you might want to minimise resistance or maximise a velocity factor hence a larger diameter of the return wire.
**Velocity factor is largely determined by the insulation material, not
the size of the conductors.
I suppose my real interest here is should having an interconnect return wire with a larger diameter than the signal wire have theoretically a €śbetter€ť sound, i.e. less noise, than an interconnect cable with wires of equal diameter - all other things being equal? And why?
Further would there be a €śtheoretical€ť benefit in having a separate return wire from just one point on each unit fanning out to a central contact point?
**No.
Another thought should there be a continuity between interconnect cables and within units with regard to wire material and fabrication between the source, pre and power amps? Would that reduce reflections?
**What reflections? There are none to start with. Most cables are less
than 3 Metres. Even with cables of 1,000 Metres or so, there will be no
reflections of significance.
Audio is really easy. You need to worry about these sorts of things at
very high radio frequencies.
--
Trevor Wilson
www.rageaudio.com.au
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