Ethan Winer Builds a Wire Null Tester

[Ethan Winer]

Turn off autoranging and hold down the relative button until it beeps/zeroes. The fixed test cable will be zeroed out and the cable under test will show just its value- saves doing the maths.

Totally awesome, I had no idea! I just tried it and it works. Thanks!

 

[DonH56]

To me most all signals are analog, but I am an analog guy. Since my day job involves testing PCIe/SAS/SATA Phys I am pretty comfortable believing all the signals and various waveform measurements are analog in nature (though we use a DSO to do some of the tests, go figure). The digital part happens when a comparator or latch someplace extracts the signal and decides it is a one or zero for the logic circuits. And of course the logic circuits are dealing with thresholds, hysteresis, bandwidth and skew, and all that other nasty analog stuff. A bit stream is digital once it is in the digital circuit blocks but even there things like timing closure are where the digital guys spend a lot of time. At the circuit (transistor) level it is analog; I don't care what those RTL guys say.

Aside: Ethan, great to see you posting here again! Hope life has gotten a little more relaxed; you were swamped last time we "spoke". And BTW my family still enjoys your cello rondo, but I still say it needs trumpet...

 

[restorer-john]

John, did you actually make sound files from those? That would be... delicious.

Yes, I sent the signal into my (at the time in 2007) standalone HDD CD recorder (Yamaha CDR HD1300) and recorded real time CDRs of a few tracks with each 'natural interconnect'. There may be some of the original tests still on the internal HDD of that machine, but it is stored away.

I've got some strawberries here, they're still in season (just), maybe I should update my Natural Interconnect test?

Actually, Amir should feed coaxial 24/192 through some of his garden vegetables and use the AP to analyze the resultant signal!

 

[Pluto]

The biggest farce of all with cables is the idea that the signal path is optimal in one direction – completely neglecting the unfortunate fact that audio is an AC thing and the electrons spend just as much time going in one direction as the other. Anyway, try this dose of logic....

If a cable is directional it must, by definition, be exhibiting a diode effect to some degree.
Any solid state diode [of which humanity is aware] is a highly non-linear device.
Ergo, any cable exhibiting directional behaviours MUST be inherently non-linear and, therefore, unsuitable for audio.

OK, I'll get back in my box now.

 

[invaderzim]

Isn't the directional part of some cables based mostly or completely on which side of the cable the shield is grounded?

My understanding is the 'idea' there is to ground it at the source side to reduce the amount of signals picked up by the shield that get delivered to the next amplification stage in the system. These are with wires that have a ground also going through the center of the shield with the signal. I don't know if the ground being connected 3 feet away stops noise signals from making it to the amplifier though. I would think it would be easy to test with a wire designed that way, just measure the noise floor on the amp with it one way in an area of a lot of electrical interference and then reverse it and measure again with it in the exact same area. Something a bit like Mr Carlson did with capacitors:

I guess some of the really expensive wires may claim other reasons but that is what I've seen on any DIY ones designed to be 'directional'.

 

[Deleted member 2944]

The biggest farce of all with cables is the idea that the signal path is optimal in one direction – completely neglecting the unfortunate fact that audio is an AC thing and the electrons spend just as much time going in one direction as the other. Anyway, try this dose of logic....

If a cable is directional it must, by definition, be exhibiting a diode effect to some degree.
Any solid state diode [of which humanity is aware] is a highly non-linear device.
Ergo, any cable exhibiting directional behaviours MUST be inherently non-linear and, therefore, unsuitable for audio.

OK, I'll get back in my box now.

Wire itself is not directional, but the shielding configuration of a cable might make it so. Some interconnect cables have the shield only attached at one end to break possible created loops. If reversing a cable like that it's possible to create a buzz/hum/etc that might not have existed in the other direction.

Dave.

 

[Pluto]

Wire itself is not directional, but the shielding configuration of a cable might make it so

The advocates of ‘directional cable’, typically, don't seem interested in oddities of wiring that, sometimes, make an earth connection at only one end of a cable, a useful ploy. In any case, such solutions are usually to help with a major issue – “this way round, it hums. The other way round, it doesn't”.

Most of the arguments about directional cable seem to be more along the lines of how much more expressive the second fiddles become with the cable the ‘right’ way round. Oh, and the soundstage is just soooo much wider that it barely fits in the room

 

[Deleted member 2944]

Cable "advocates" judge (almost exclusively) with subjective evaluation....which is impossible to argue with.
But the fact of the matter is, objectively, some audio cables 'are' directional and the little imprinted "arrow" might indicate something meaningful. And the cable, depending upon the components it's connecting, might perform better in one direction or the other.
A cable "advocate" probably wouldn't understand (or care about) the reason why.

Dave.

 

[sergeauckland]

Cable "advocates" judge (almost exclusively) with subjective evaluation....which is impossible to argue with.
But the fact of the matter is, objectively, some audio cables 'are' directional and the little imprinted "arrow" might indicate something meaningful. And the cable, depending upon the components it's connecting, might perform better in one direction or the other.
A cable "advocate" probably wouldn't understand (or care about) the reason why.

Dave.

I do argue with it, I tell them they're wrong, and they're imagining things unless the evaluation was done double blind and with statistical validity. Statements of "I heard it so it's true' without corroborating evidence make my piss boil.
S

 

[DonH56]

An XLR cable may have the shield lifted at one end to break a ground loop or other ground imbalance issue.

Single-ended cables like RCAs must have a current return path so you cannot lift the shield at one end. That said, if there is more than one shield layer (some coax designs use an inner and outer shield), then the outer shield could be lifted at one end. That is not the case for the vast majority of standard interconnects. And the only way it would matter is in a high-noise environment with high source and load impedances. That goes for "digital" coax for S/PDIF and AES (single-ended) as well.

The bar on the non-polarized film cap tells which is the outer layer so you put put the outermost layer at ground or the low-impedance (driving source) side of a circuit if you wish. Electrolytic caps are polarized and have (+) and (-) signs on them.

I have read marketing blurbs describing the orientation of the shield wrap as directional and influencing the EM fields. That is not what I learned in any of my basic circuits, electromagnetic (EM), or microwave classes about how conductors in contact with each other work, but I don't sell cables for a living.

The only directional cables I have seen that can lay some claim to such are those that include a compensation network at one end. You can make an argument whether the network should be at the source or load end. I tend to think such arguments aren't of much value at audio frequencies but probably just me.

As I've said before, cables make a significant difference in my system, and I have proven it in objective and subjective testing as follows: pull the cable, and the sound goes away; put it back, and the sound returns. That is a significant difference easily heard and readily verified by measurements. I take the rest with a block of salt.

FWIWFM - Don

 

[Deleted member 2944]

Unbalanced interconnect cables (even simple coax) don't necessarily require a return path via a shield. (I've seen some cables that are constructed like that.)
This would require a return path elsewhere though.....which probably exists in many cases.
It 'might' yield a better hum/noise rejection scheme in a peculiar setup. It's difficult to say.

I do like your final point about objective and subjective testing though. Excellent!

Dave.

 

[DonH56]

Yah, you could depend upon the safety ground, a separate chassis ground, or whatever, but as an RF guy getting the return current away from the source is a big no-no. I have lots of examples of how things go wrong when you screw up the ground layout. Too many people forget current is a loop and how EM fields work. At multi-GHz data rates, let alone 10's to 100's of GHz pulses, breaking the ground path or just getting it too long is death. At least for signal integrity.

 

[mansr]

Single-ended cables like RCAs must have a current return path so you cannot lift the shield at one end. That said, if there is more than one shield layer (some coax designs use an inner and outer shield), then the outer shield could be lifted at one end.

I have an Audioquest RCA cable (didn't pay for it) consisting of a (presumably) twisted pair surrounded by a braided shield connected at one end only. It has some odd behaviour up around 40 MHz.

 

[JJB70]

The thread on computer audiophile discussing this video is quite eye opening, it would appear a lot of users of that forum really buy into cable myths.

 

[Pluto]

the cable, depending upon the components it's connecting, might perform better in one direction or the other

Well, I would dearly love to know what physical parameters (other than a connector fault) could possibly cause such a phenomenon.

 

[DonH56]

I have an Audioquest RCA cable (didn't pay for it) consisting of a (presumably) twisted pair surrounded by a braided shield connected at one end only. It has some odd behaviour up around 40 MHz.

I figured as soon as I posted there would but a bunch of "but I've got this cable" posts... If you have a noise problem, it can help. If it works. If it is actually competently designed for RF. And all that jazz.

I'd guess the shield is acting like a tuned stub (or quarter-wave transformer) around 40 MHz.

 

[Pluto]

Single-ended cables like RCAs must have a current return path so you cannot lift the shield at one end.

If the audio has an alternative path to earth you might be able to get by (at audio frequencies) with only one, or even neither end's shield connected. But I'm not saying you should, no way!

 

[mansr]

I figured as soon as I posted there would but a bunch of "but I've got this cable" posts... If you have a noise problem, it can help. If it works. If it is actually competently designed for RF. And all that jazz.

I didn't mean to suggest it was in any way useful.

I'd guess the shield is acting like a tuned stub (or quarter-wave transformer) around 40 MHz.

That would be my guess as well.

 

[Blumlein 88]

The thread on computer audiophile discussing this video is quite eye opening, it would appear a lot of users of that forum really buy into cable myths.

You should try and read the thread I had there about 4 years ago. I asked if anyone had evidence interconnects sounded different. I asked if all anyone had was anecdotal listening impressions to refrain from commenting. Most of the thread was angry posters who couldn't stand to see the topic addressed any other way.

Well I see it was actually 5 years ago now.

https://www.computeraudiophile.com/...-than-fully-transparent-at-audio-frequencies/

 

[Deleted member 2944]

Well, I would dearly love to know what physical parameters (other than a connector fault) could possibly cause such a phenomenon.

I just told you.....in the previous posts. I'm sorry, maybe I'm not making it clear.

I'm certainly not advocating for cables that are constructed in this way. Just pointing out that they're out there in the field, in use by possibly delusional audiophiles. Just the messenger here.

Dave.