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Comparing the tone of three different "boutique" cables

#421
Serious +1 to delta7fred's suggestions. If you look at this pic:

http://www.topsail.org/goodies/AP500M/S5000921.JPG

You'll see one example of what he's describing. I've got a long cable coming from the signal generator terminated in 50 ohms (the green BNC thing on the T to match the generator and cable impedance). Then, I'm using a 12k series resistor to simulate the pickup impedance into the preamp - I was testing the preamp here. There's a parallel capacitor on this test setup for RF bypass, since I have a 5 kw AM broadcast station less than a mile away.
 
#423
delta7fred said:
You probably need more than just a capacitor !!!!!!!!!!!!!!!!
Click to expand...

:D It's enough for this setup to scrub the RF picked up on the cable shield from the signal generator. It's not volts of RF, just a few mv because the grounding in the shop is decent. I'd need a screen room to get rid of all of it tho.

Still, it's a different story entirely when I am doing RF measurements.
 
#426
relwof said:
You might be just simplifying it a bit (and I'm not sure I'll be making it LESS confusing) but the way I understand balanced connections, it seems you left out a few key parts.

First, the "complementary signals" have to be treated on both ends, not just the receiving end. Balanced connections take a signal, split it in two, reverse the phase on one line, send those two lines (+ground) through the cable, and then reverse one line's phase again on the other side before mixing the two lines to recreate the signal. So the polarity actually gets reversed twice. Mixing a signal with it's direct inverse (out of phase) cancels it out. If you just mixed the two signals without "re-flipping" the phase, you'd end up with nothing BUT the noise.

Signal "a" becomes A and -A on the cable. Noise comes in giving you A+N and -A+N. Then on the other end you flip it back, so -A+N becomes A-N. This converts the reversed line back to the original signal, AND reverses the phase of the noise on that line, so now you're mixing (A+N) and (A-N) getting A+A. N and -N cancel each other out.

So part of the magic in combating noise over a balanced connection is this signal split-flip-flip-mix process, which requires balancing circuitry on both ends, which is in the connected gear, NOT in the cable. An extra wire doesn't help this happen unless you're connecting a balanced output to a balanced input.
Click to expand...
Well, of course. When I said that the signals on the twisted pair in a balanced connection are complementary, I assumed that folks (most folks, anyway) would know what that means (one is the reverse polarity of, sometimes erroneously called "out of phase" with, the other). As to the extra wire not helping with noise rejection in an unbalanced application, that was precisely my point. My apologies if I wasn't clear.
 
#427
At some point, when this thread reaches its conclusion, would someone be so good as to excise all the digressions, class-clown posts, struggles for clarity, redundant arguments, etc. and make a succinct article for average users explaining the ultimate findings in one easily-digested page or two?

Like, "What's the most awesomest cable?"

"Here, read this and shut up."

On behalf of humanity and future generations, I thank you. ;)
 
#429
Actually, I have in fact done exactly that, at least to the extent my research has gone so far. http://www.ovnilab.com/articles/cables.shtml

I will probably add Whirlwind, Mogami, and maybe one more high-end boutique cable like Asterope or Vovox to the list sometime in the next couple months. And I still have more tests to perform on the existing cables. One is I intend to test transient response using steep pulse waves and a scope--this I will be able to do in just a couple of weeks from now. Also I am not quite satisfied with the results of my distortion and noise testing. I can believe that maybe they all really do have identical distortion qualities, but I'd like confirmation of that. And while they did not all test identically for noise, the results were surprisingly similar--I expected greater differences, for example between cables with one layer of thin insulation versus cables with multiple layers of thick insulation. I already have a professional-grade audio analyzer, but I'm open to suggestions about how to get the most useful results from it, or from other devices.
 
#430
Bryan R. Tyler said:
The ability to happily accept that a previously held-to theory is incorrect when new evidence presents itself is tough thing to do, and the basis of all good science. Good job.
Click to expand...
True, but this issue is hardly closed. All the current experiment has determined is that the software returns similar measurements of the specified parameters of the cables tested - this is supporting evidence, but is hardly conclusive. It's time for the OP to have a friend come over and blind the cables, and then perform a blind audio test and try to identify them. If he can't, I'd call it solved -- if he can, however, then we need to examine additional parameters and possibly revisit some of the axioms on the current experiment -- accurate signal resolution by the software on his particular hardware combination, for example.

Now, someone go get some tape, and give those things a blind listen! :)
 
#431
bongomania said:
Actually, I have in fact done exactly that, at least to the extent my research has gone so far. http://www.ovnilab.com/articles/cables.shtml
Click to expand...
Well, splendid.

So, [drumroll] bottom line (as I read it): Except in a very few extreme cases, no instrument cable under twenty feet in length will make an audible difference in tone within the normally accepted range of human hearing, <16kHz?

Yes/No?
I already have a professional-grade audio analyzer, but I'm open to suggestions about how to get the most useful results from it, or from other devices.
Click to expand...

Don't look at me, I'm a BFA, not an EE. ;)
 
#432
Bongolation said:
bottom line (as I read it): Except in a very few extreme cases, no instrument cable under twenty feet in length will make an audible difference in tone within the normally accepted range of human hearing, <16kHz? Yes/No?
Click to expand...

Mostly yes. There are caveats and (as you say) some outlying cases, but aside from those, the two bottom lines are:
1) Under 20', the tone below ~16 KHz will be identical with all cables.
2) An active instrument (or buffer pedal) will totally cancel out any audible effects any cable might have.
 
#434
Great article bongo, and forgive a noob question here, but what is all the talk of cable capacitance about? I know little about electronics (another BFA here) and am curious as to what effect capacitance has on tone, spelled out in layman's terms. Is cable capaitance really only relevant on passive basses as your article suggests? thx!
 
#435
engedi1 said:
Great article bongo, and forgive a noob question here, but what is all the talk of cable capacitance about? I know little about electronics (another BFA here) and am curious as to what effect capacitance has on tone, spelled out in layman's terms. Is cable capaitance really only relevant on passive basses as your article suggests? thx!
Click to expand...

it's only relevant on passive basses.

a higher capacitance causes highes treble (higher frequencies) to be diminished over time. Thus, the output "sounds" more "bassy", but it's only because there's less treble.
 
#436
Related question:

Some guy was mentioning he was concerned about the "latency" of his instrument cables.

I seem to remember that this is another imaginary issue dreamed up by crooked audiophile marketing...but that's all I recall.

What is he talking about? Can you link to a credible explanation and debunking of it if it's jive?

Thanks to anyone who can help!
 
#437
If they all have nearly the same resistance, they all have nearly the same conductance. We're talking about a small fraction of an ohm difference in most cases. Given that most of the technical parameters that cable sellers go on about, like skin effect and resonance, are only relevant at MHz and GHz frequencies, then resistance is really the only parameter that would make a difference--and higher resistance causes lower signal levels, not any measurable slowing of the signal (latency).

Latency in the digital domain is dependent primarily on processor speed, not the cables. If too much data is sent at once, then cable bandwidth does come into play. But in the audio domain, cables have identical bandwidth, according to my distortion tests.

So latency from an audio cable is a crock.
 
#438
Bongolation said:
Related question:

Some guy was mentioning he was concerned about the "latency" of his instrument cables.

I seem to remember that this is another imaginary issue dreamed up by crooked audiophile marketing...but that's all I recall.

What is he talking about? Can you link to a credible explanation and debunking of it if it's jive?

Thanks to anyone who can help!
Click to expand...

Electricity travels at the speed of light, iirc. Unless he's playing on the sun, he's worried about nothing
 

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