Desirable electrical qualities for line level interconnects

[mansr]

For reference, I measured a 2-metre RG-59U coax cable.

DC resistance (round-trip): 0.55 Ω
Capacitance: 149 pF
Inductance (round-trip): 3 μH

The frequency response is flat to at least 50 MHz (that's the limit of my function generator). I paid about $10 for this cable.

 

[mansr]

^^^ You do know that string is not a conductor, yes?

https://www.revk.uk/2017/12/its-official-adsl-works-over-wet-string.html

 

[DonH56]

You're as bad as me... I couldn't pull up the article, but IIRC they used wet string, not dry, and furthermore didn't they have to use salt water? DI water is not terribly conductive but salt ions will do the trick. In any event the idea of using string for ADSL (or most any other transmission) seems all wet to me.

 

[Djsedaw]

What!..... The man in the audiophile shop said it would extend the sound stage and give a trans dimensional sound.

 

[mansr]

You're as bad as me... I couldn't pull up the article, but IIRC they used wet string, not dry, and furthermore didn't they have to use salt water? DI water is not terribly conductive but salt ions will do the trick. In any event the idea of using string for ADSL (or most any other transmission) seems all wet to me.

Yes, they used salt water.

 

[DonH56]

What!..... The man in the audiophile shop said it would extend the sound stage and give a trans dimensional sound.

Silly boy, that's only if you go for the additional surround cans. A step-up from the base toucan, errr, two-can solution.

 

[amirm]

I don't know what use the single can setup at each end is. It is not even stereo! I have built one for surround sound:

It has true soundstage.

 

[babysnake]

A thought occurs

Does this logic apply to speaker cables too?

Within certain fairly generous parameters, they're all the same electrically?

The rest is varying degrees of bling

 

[babysnake]

Which would presumably be salty wet rope, as distinct from wet string, no?

 

[sergeauckland]

Some may remember the European AES show a few years back when Canford Audio had a fish tank with real fish swimming about and two pieces of string carrying AES-EBU digital audio running through the tanks. Digital audio was transmitted perfectly for the four days of the show.

I have personally sent AES-EBU through my body, holding on to the two ends with wet hands. Using a sensitive S-PDIF receiver that was possible a bit more sensitive than the normal 0.2v, I got audibly perfect transmission for the few minutes I cared to hold on to the ends.

AES-EBU and S-PDIF are incredibly rugged formats.

S.

 

[sergeauckland]

A thought occurs

Does this logic apply to speaker cables too?

Within certain fairly generous parameters, they're all the same electrically?

The rest is varying degrees of bling

Yes, up to a point. An unconditionally stable amplifier will cope with any cable, the only thing that matters is the loop resistance. However, with some amplifiers that aren't unconditionally stable, these days by deliberate decision of the designer, then the capacitance and more importantly inductance of the cable matters. That's why those amplifier manufacturers will recommend certain cables which are characterised by widely spaced conductors that has the effect of reducing capacitance, but more importantly, increasing inductance, to maintain stability.

I personally will only use amplifiers that are unconditionally stable and fully short-circuit protected, as I want them to work whatever I throw at them, even putting a screwdriver across the outputs at full power...(don't ask!), and these days I don't see any good reason for any amplifier not be unconditionally stable and fully protected, but hey, HiFi has all sort of weird stuff that in my early training would have been thought of as very poor design, promoted as a benefit.

S.

 

[amirm]

Does this logic apply to speaker cables too?

Speaker cables can get long and with it, the resistance can climb high enough to cause frequency response changes with some speakers. If you stay with 12 gauge wire, you should be good for reasonable lengths. The challenge will be finding true 12 gauge as there are some fakes out there. See my article here: https://www.audiosciencereview.com/forum/index.php?threads/when-12-gauge-wire-is-not-12-gauge.3/

 

[RayDunzl]

I don't know what use the single can setup at each end is.

Remote Control, maybe.

 

[Blumlein 88]

Some may remember the European AES show a few years back when Canford Audio had a fish tank with real fish swimming about and two pieces of string carrying AES-EBU digital audio running through the tanks. Digital audio was transmitted perfectly for the four days of the show.

I have personally sent AES-EBU through my body, holding on to the two ends with wet hands. Using a sensitive S-PDIF receiver that was possible a bit more sensitive than the normal 0.2v, I got audibly perfect transmission for the few minutes I cared to hold on to the ends.

AES-EBU and S-PDIF are incredibly rugged formats.

S.

I remember reading about the fish tank. Pretty funny.

What usually will cause problems more commonly with SPDIF, and it isn't common at all, is the clock being too far out of sink. As your examples show, the transmission protocol is pretty robust.

 

[Speedskater]

For long (say over 10 feet/3 meters) RCA unbalanced interconnect:
a] a coax cable (period)
b] that coax should have a heavy braided shield (the heaver the better).
this is to reduce Common Impedance Coupling Noise currents.
c] shielding is also good to reduce EMI/RFI interference voltage pick-up.
d] reasonably low total cable capacitance is nice but not a deal breaker.

Note that Blue Jeans Cable LC-1 fits this description perfectly! But the are similar cables from other suppliers.

For short cables (3-6ft/1-2m) just about any coax will do.

 

[Speedskater]

For XLR balanced analog interconnects:
a] a Shielded Twisted Pair (STP) cable.
b] one with very symmetrical construction of the two conductors in relationship to the shield. Note that this can only be done on big expensive machines and a good Quality Control department.

Note that many pros are using unshielded Cat5/Cat6 cables. They are so symmetrical that the work better than some shielded cables.

 

[Speedskater]

Digital cables:
a] for long (in this case 30 feet/10 meters) digital cables. the Radio Frequency Characteristic Impedance (75 or 110 Ohms) is important.
for short cable the RFCI is not important.
b] at these low digital frequencies, the connector impedance is never, ever important.

 

[Blumlein 88]

People have a prejudice against optical toslink for digital. It hasn't been justified for many years. It can be good for long digital runs. Short ones too.

 

[mansr]

What usually will cause problems more commonly with SPDIF, and it isn't common at all, is the clock being too far out of sink.

S/PDIF signal encodes its own clock (biphase mark). Are you referring to the receiver failing to lock onto the clock? I don't think I've ever had that happen.

 

[Blumlein 88]

S/PDIF signal encodes its own clock (biphase mark). Are you referring to the receiver failing to lock onto the clock? I don't think I've ever had that happen.

Yes the receiver failing to lock onto the clock. I see I both mis-spelled synch as sink. And gave the wrong idea. I've run into it a few times. One device is too far from the other in clock speed and they don't lock up. Or it won't stay locked up.