Cables, electrons, power- think again

Tzs503gp

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I don?t pretend to grasp what?s happening. But it seems we MUST reimagine exactly what the cable does:

https://youtu.be/bHIhgxav9LY



 

Tzs503gp

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There a response video to the first one I posted in which the guy basically states, ?yes, it?s correct on a physics level, but it?s common knowledge to electrical engineers, so, meh? He also goes on to show by use of simulation software how it works. Supposedly it?s basic transmission line theory.

https://youtu.be/VQsoG45Y_00

Are speaker/ hifi cables not transmission lines?

I must say, this is a revelation to me. And that?s what pisses me off. If this is basic engineering knowledge, why have our venerable electrical engineers on the forum never even mentioned this. These effects are fundamental to the interactions that come into play in hifi cables.

Yes, we?ve been told before: ?but it?s inaudible?.
 

fredeb

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The information worth considering are high capacitance loads , which may cause gremlins in power amplifiers . Making the load more difficult to drive , or even causing HF oscillation .

Short runs of adequate speaker cable for stereo . Capable of easily bearing the power load and bandwidth . Good quality stranded copper cable of adequate gauge .







 

Shonver

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Tzs503gp said:
Are speaker/ hifi cables not transmission lines?

I must say, this is a revelation to me. And that?s what pisses me off. If this is basic engineering knowledge, why have our venerable electrical engineers on the forum never even mentioned this. These effects are fundamental to the interactions that come into play in hifi cables.

Yes, we?ve been told before: ?but it?s inaudible?.

Sure, they are indeed transmission lines. However, an important factor to consider when talking transmission lines is the signal bandwidth. The simple truth is that in the bandwidth that audio signals occupy, and considering the electrical characteristics that a reasonably good cable possesses at those frequencies, cables do not affect the audio signal. Thick enough twin flex will do a sterling job as a loudspeaker cable.

Why then, you may ask, do I hear a difference in my system when I swap out cables? I hear it clearly! And so does my wife/buddy/neighbour???!!!

The answer is both simple and terrifying: if it is true that cables (a non-exotic, non-cheapskate, but reasonably good quality cable) do not affect the signal within the audio band, then it must be affecting signals outside the audio band.

Why is this even a factor, though?

"Signals outside the audio band" essentially means radio frequency (RF). Electronic components - even those that are claimed to have been developed exclusively for audio applications - have the ability to operate well into the RF spectrum. Some components even change their characteristics at those frequencies; a capacitor becomes inductive; an amplifier becomes an oscillator. The higher the performance of the components used, the higher the risk that a circuit will be unstable (e.g., super-fast diodes, transistors and op amps; ultra-low esr capacitors). The circuit layout is also a component, albeit not an obvious one (those pretty symmetrical layouts loved by audiophiles pose a risk because they are likely not the most optimised version). And this is where the rubber hits the road: how stable is an audio device (usually power amps are the most vulnerable) when loaded differently above the audio band - the way different cables do? Yes, it is outside (above) the audio band that differences between cables have been demonstrated (measured) to be greatest.

How does "outside the audio band" affect me? Let's summarise:

(1) A reasonably good cable won't affect the audio signal
(2) Differences between cables manifest most markedly in the RF frequencies (above the audio band)
(3) Electronic components and sub-circuits in audio equipment have the inherent ability to act and interact in the RF band

And what are we left with? We are left with the ability of the design engineer to look beyond just the audio spectrum; to design-in immunity to signals and loadings that fall outside the "base band" (a term borrowed from communications engineering). Step up to any unsuspecting electrical engineer and tell them that you changed basically good cables for something truly audiophile and the result was a transformation of your sound quality. They might laugh in your face, because this should not happen. It should not happen if your equipment had been competently designed. And by competently, I am referring to a design that does not only have a functional audio circuit, but that has been implemented and further developed to be bullet-proof.

But - even so - I don't hear RF signals! Why are you making this an issue??!!

The different permutations of what can go wrong when RF breaks into an audio circuit or if an amplifier goes into RF oscillation - sometimes continuously, sometimes occasionally/conditionally - is dependent on the specific circuit and its characteristics (for instance, a different layout will have its own characteristics). However, an example of how an RF behaviour can affect the audio band is when a transistor saturates due to unstable or uncontrolled behaviour in the circuit. The circuit can momentarily (or continuously) latch up. It's like your amp has been momentarily hijacked, and can't do its amplifying thing; this results in distortion. Effects like short-term blanking of the signal (too short to be obvious as blanks, but there, nevertheless) or playing a rectified version of the audio (only positive or only negative cycles).

So, yes: I am saying that if your equipment does the cable trick then it is lacking that extra mile of refinement (development, technically speaking).
 

Cuco

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So you're saying we have unrefined equipment that's why we need good cables, pebbles, cable lifters, isolation platforms, squash balls?
 

Tzs503gp

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And you?re also saying, in my case, a Mark Levinson 23.5 is an unrefined amplifier. You?d know better than me, for sure. But I?m sceptical. Don?t get me wrong though. I?m not saying my amplifier is blameless. I agree that the difference heard by changing cable is the manifestation of the difference inherent to the cable, acting on the amplifier, and furthermore brought to audibility by speakers of adequate transparency.
 

Cuco

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Your Mark Levinson 23.5 is extremely unrefined. Let me know if you sell it.  :). I need someone to translate your last sentence. 
 

Shonver

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Tzs503gp said:
And you?re also saying, in my case, a Mark Levinson 23.5 is an unrefined amplifier. You?d know better than me, for sure. But I?m sceptical. Don?t get me wrong though. I?m not saying my amplifier is blameless. I agree that the difference heard by changing cable is the manifestation of the difference inherent to the cable, acting on the amplifier, and furthermore brought to audibility by speakers of adequate transparency.

No worries. I'm not taking any pot-shots. I have no doubt that it's a terrific product. (But I warned that it the truth would be "terrifying"). If your amp needs a specific cable to make it perform to its potential and you are able to provide such, I'm sure you'll have a happy experience. It's just that these special requirements otherwise show up the products for "what it is". I've owned a few Alfa Romeos, so I know how it goes; only the owner knows where the joy lies.

Don't worry about what people say on the internet  ;D
 

scrarfussi

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Tzs503gp said:
I must say, this is a revelation to me. And that?s what pisses me off. If this is basic engineering knowledge, why have our venerable electrical engineers on the forum never even mentioned this. These effects are fundamental to the interactions that come into play in hifi cables.

Yes, we?ve been told before: ?but it?s inaudible?.


This is answered 15:22 on the video Electrical Engineers view  the circuit differently they look at current and resistance and power and forget all the physics stuff
 

scrarfussi

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Shonver said:
So, yes: I am saying that if your equipment does the cable trick then it is lacking that extra mile of refinement (development, technically speaking).

Well technically speaking there is no perfect amplifier or perfect preamp or dac or speaker. No Such thing. Every piece  is lacking that extra mile . That's why the manufacturers themselves come up with better versions and upgrades and better technology

if you cant hear a difference then uhmm  maybe its the ears and not the equipment
 

Shonver

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scrarfussi said:
if you cant hear a difference then uhmm  maybe its the ears and not the equipment

Valid comment, had I denied that cables make a difference!

Edit: What I said was that cables do not affect the audio signal directly, but can (for instance) upset an amplifier such that it distorts the audio signal. So no denial that cables can make a difference.
 
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