• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). There are daily reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

"Low Capacitance" Cables?

rwortman

Addicted to Fun and Learning
Joined
Jan 29, 2019
Messages
653
Likes
580
I would not worry a whole lot about the capacitance as the driving source usually has a low impedance and the preamp or amps usually have a high input impedance.
The cable capacitance is a shunt to ground. The input impedance of the following gear has little effect.
 

dlaloum

Major Contributor
Joined
Oct 4, 2021
Messages
1,826
Likes
1,266
It's been over 10 years since I searched for low C cabling - and that was when I was deep into what can be achieved by varying the loading on MM cartridges...

MM cartridges are EQ'd by design, by the circuit formed by Inductance, resistance and capacitance.... and the "holy grail" of flat frequency response can best be approximated by adjusting those 3 parameters... which led me down a series of (interesting) rabbit holes.

But yeah the short answer is ... shorten the cable.

Shielding - approach with caution as it can impact on capacitance... but it can be a boon for very low level signals prone to various kinds of external interference.

I would not have thought it to be an issue (shielding) for line level interconnects (at most reasonable lengths... !! ) - and you have to be careful with how you wire shielding and ground to ensure you don't get the dreaded ground loop hummmmmm

I ended up using BluJeans LC1 as a nice compromise - wasn't the lowest C I could find, but nicely made.
 

Holdt

Senior Member
Joined
Jun 10, 2022
Messages
321
Likes
216
This thread is about a non-issue. Just avoid the absolute cheapest stuff and you are more than fine.

Lots of stuff in production industry wouldn't work if it was so sensitive as you seem to think it is. :)
 

tuga

Major Contributor
Forum Donor
Joined
Feb 5, 2020
Messages
3,601
Likes
3,700
Location
Oxford, England
The Audioblast cables claim to be well shielded but higher in capacitance: 38.2 pF/Ft. But should that be low enough for the preamp? As far as I can tell trying to put all the answers here together, it should be fine(?) Otherwise I can just get the lower capacitance RCA cables from Benchmark, using the Belden cable at 16.2 pF/Ft capacitance. But is it well shielded enough to put aside worried about noise interference?

If you're in the UK you can order a short single-ended Blue Jeans LC1 here: http://www.bluejeanscable.co.uk/store/audio/index.htm
 
OP
MattHooper

MattHooper

Major Contributor
Joined
Jan 27, 2019
Messages
4,472
Likes
7,153
What do you think that the shield does?
And what is it shielding from (E-field, magnetic, RF)?

Yes, but literally every cable is shielded. And yet some designs are still more susceptible to noise than others. That's why designs like star quad exists, right?


I would not worry a whole lot about the capacitance as the driving source usually has a low impedance and the preamp or amps usually have a high input impedance.

Thanks, but as an electronics dunce I wouldn't immediately understand the implications of one having a low impedance vs the other having a high impedance.
Many of the answers are assuming a level of technical familiarity that I struggle with, unfortunately.


That is not at all true for the cart to phono stage though… and most carts say use 100-200 pF, so it is not a crime to have a bit of capacitance, and the connectors might add some as well.

Oddly I made some short 1M XLR to RCAs (StarQuad Mogami), and one of the speakers pick up the radio station now when the volume is railed…
I’ll need to put RCA plug with resistors on the unused input and see if that mitigates it.
I have no idea where and how it is sneaking in.

I presume they were shielded?

And the balanced gear says do not worry about the cable, so I can see your chin scratching…

Thanks. I came in to the thread figuring most of what I was "worrying about" would be a non-issue, but wanted to double check. As to the details, I'm still scratching my chin a bit. But that's me....
 
OP
MattHooper

MattHooper

Major Contributor
Joined
Jan 27, 2019
Messages
4,472
Likes
7,153
I'm surprised with the continued discussion. @sq225917 has told you everything you need to know.

Matt, it doesn't matter in the slightest due to the lengths you are running and devices you are connecting. Buy whatever you like the look of.

Hi Blumlein88

I have presumed that in all likelihood it wouldn't matter which cables I chose. But I wanted to make sure, and also try to grasp at what point the the type of design/shielding/capacitance would be important or not. E.g. would the cables hanging out the back of my rack within a foot or so of power bars, or being within inches of power cables, entail I should be looking at good interference rejecting cables or not? Or if lower capacitance would be more important?

The problem is I really, really do have some sort of dyslexia regarding electricity. I don't have a technical aptitude like so many here and electrical theory has always been extremely hard for me to grasp. So many are throwing out terminology and calculations that leave my head spinning. As well, since some of the contributions may be more or less informed or correct, I'm not in a position to just know: "oh..what THAT guy just said is the right answer."

I asked for it. But really grasping the answer beyond "it doesn't matter what you buy" isn't easy, unfortunately.

Thanks for your replies - I do have confidence that you know what you are talking about. My understanding is the problem.

It's a real hassle cabling my system so I wanted to do it once and do it right. But I guess I won't sweat the details too much.
 
OP
MattHooper

MattHooper

Major Contributor
Joined
Jan 27, 2019
Messages
4,472
Likes
7,153
Thanks for all the replies everyone!
 

rwortman

Addicted to Fun and Learning
Joined
Jan 29, 2019
Messages
653
Likes
580
If you use that calculator I linked and plug in 700 ohms output impedance and 300pf of capacitance(10 feet at 30pf/ft), for example, you get a cutoff frequency( the frequency at which it rolls off)above 750khz. Way above the audio band. Balanced audio cables achieve most of their noise rejection by the input of the component rejecting common mode noise, that is noise that is presented on both plus and minus connections. Star quad geometry gets its additional noise rejection because the way the wires are wound results in both poles picking up a more identical signal, thereby being more perfectly cancelled out at the component input. The fact that the star quad cable has more capacitance is because there is twice as many wires carrying the signal and the capacitance is formed by the wires as one plate of the capacitor (What is a capacitor)and the shield as the other. More area on the wire “plate” equals more capacitance.

Using the same calculator, 10,000pf of capacitance with your 700 ohm output impedance puts the cutoff frequency at around 22khz. So you would need 10 feet of cable at 1000pf per foot before you got close to an audible frequency response problem. As far as the noise shielding goes, I always figured if you cant hear noise when the music isn’t playing, you don’t have a problem. Some audiophile writers have suggested that inaudible noise can cause audible artifacts but that sounds like nonsense to me.
 
Last edited:

restorer-john

Grand Contributor
Forum Donor
Joined
Mar 1, 2018
Messages
10,392
Likes
29,989
Location
Gold Coast, Queensland, Australia
The star quad geometry used by several manufactures has twice the capacitance (in my measurements) as compared to non-star balanced. Balanced (hot/cold/gnd) cables has capacitance way in excess of single core shielded (coax).

If coax wasn't such a bear to work with, I'd make all my cables with it. But I like flexibility and my cables to stay where I want them, not writhe around and twist like an eel.
 

rwortman

Addicted to Fun and Learning
Joined
Jan 29, 2019
Messages
653
Likes
580
But I like flexibility and my cables to stay where I want them, not writhe around and twist like an eel.
I make my unbalanced interconnect cables using Mogami instrument cable. It is coax and has a bit higher capacitance but is nice and flexy. Guitar players don’t want stiff cables. The only thing I use “real” 75 ohm coax for is digital interconnects.
 

restorer-john

Grand Contributor
Forum Donor
Joined
Mar 1, 2018
Messages
10,392
Likes
29,989
Location
Gold Coast, Queensland, Australia
I make my unbalanced interconnect cables using Mogami instrument cable. It is coax and has a bit higher capacitance but is nice and flexy. Guitar players don’t want stiff cables. The only thing I use “real” 75 ohm coax for is digital interconnects.

Good to know. I should buy a roll of Mogami as my last roll of 2 core shielded is going 'off' inside the jacket. The copper is discolouring making soldering a nightmare. A pity as there is still about 70M on the roll...

I have a bunch of 50 and 75R coax cables BNC equipped all over my test bench for looping various instruments. You cannot use 'normal' audio cables with fast rising edges...
 

sam_adams

Addicted to Fun and Learning
Joined
Dec 24, 2019
Messages
522
Likes
1,191
For many years Mogami has recommended their W3173 AES/EBU long run cable for analog audio use. Through precise geometry its impedance is well controlled. It has both low capacitance and low shield resistance. It is much easier to work with than star-quad since it's only two conductors and the shield. The one drawback is the ≈8mm outside diameter which makes choosing RCA connectors a bit of a pain. Available at Redco.
 

Holmz

Major Contributor
Joined
Oct 3, 2021
Messages
1,782
Likes
1,040
Location
Australia
Yes, but literally every cable is shielded. And yet some designs are still more susceptible to noise than others. That's why designs like star quad exists, right?

Not all cables have a shield. (Almost all of the red and white and yellow cables from the store have no shield.)
And most of the superfine TT tone arm cables are just 4 wire and no shield.
One sometimes has the in a metal arm, and they always get them into a terminal block pretty smart-quick to go to a better cable, which would be too stiff for a tonearm.

The starquad https://en.wikipedia.org/wiki/Star_quad_cable Geometry is like a twisted pair in that the twist is designed to cancel out magnetic field inducing a current over the long haul. The quad part is to also cancel out inducing a current over the short haul of a field limited on length.

For the electric field, the shield is designed to take care of that.

If one has 50 or 60Hz hum, then the StarQuad takes care of it on the IC side.
One can still have ground loops and magnetic fields, but it does not a whole lot get easier going to a different geometry, other than maybe coax.



Thanks, but as an electronics dunce I wouldn't immediately understand the implications of one having a low impedance vs the other having a high impedance.
Many of the answers are assuming a level of technical familiarity that I struggle with, unfortunately.
...

I’ll give you honesty.
Most claim to know more than can be believed.

A source that has a low output impedance can drive high inductance and high capacitance loads more easily than a high output impedance.
The values were are talking about are pretty small.
Some speaker cables have high capacitance, and when they get long, the amount of capacitance goes up.
If the cables are long, then go for low capacitance and inductance values. (Your’s are short.)



I presume they were shielded?
...

Correct, star quad Mogami with some cheap RCAs.
I’ll put different RCAs on the end.

They are also going into a different amp (an old NAD 3220), and the volume was railed to 100%.
Maybe it coming in through another path like power or speaker or ??



Thanks. I came in to the thread figuring most of what I was "worrying about" would be a non-issue, but wanted to double check. As to the details, I'm still scratching my chin a bit. But that's me....

I dunno.
Having a lot of cable, and ones that induce currents in their neighbouring cables is a real thing.
Being careful and prudent is not a bad thing.
Length and cable routing count for a lot too.


... The copper is discolouring making soldering a nightmare.
...

Try using some rosin flux… Jaycar has it.
Sometimes it is just a pain, and some extra flux help even on new wire.

I also forget how much of a PiTA soldering wires is… but having the components and getting the cables made up is worth it on a Sunday.
 

rwortman

Addicted to Fun and Learning
Joined
Jan 29, 2019
Messages
653
Likes
580
I use Mogami 2524 for unbalanced interconnects. https://mogamicable.com/category/products/W2524.php
There is no need to use shielded twisted pair wire for RCA plug terminated interconnects. Coaxial wire is more applicable. This wire is nice and limp with good shielding. You just have to make sure you strip off the second graphite pvc shield on the center insulator.
 

Blumlein 88

Grand Contributor
Forum Donor
Joined
Feb 23, 2016
Messages
17,143
Likes
29,860


For RCA, these are double shielded Mogami coaxial cables of low capacitance. Good for digital or analog signals. Amphenol connectors which are very, very good. This stuff is really flexible. Can get it in 6ft, 3 ft or 1.5 ft lengths. You'll pay a bit more, but not terrible pricing. They rate it as having a flex life of 16,000 flexes. Less than 20 picofarad a foot.

World's Best also make XLRs even down to 1/2 foot lengths. Neutrik or Amphenol connectors and Mogami or Canare cabling. Also flexible and low capacitance. You could build your own a bit cheaper, but hardly worth the trouble unless you were doing lots of cables or very long lengths.

Other suggestions already given have been good too.
 

Blumlein 88

Grand Contributor
Forum Donor
Joined
Feb 23, 2016
Messages
17,143
Likes
29,860
Hi Blumlein88

I have presumed that in all likelihood it wouldn't matter which cables I chose. But I wanted to make sure, and also try to grasp at what point the the type of design/shielding/capacitance would be important or not. E.g. would the cables hanging out the back of my rack within a foot or so of power bars, or being within inches of power cables, entail I should be looking at good interference rejecting cables or not? Or if lower capacitance would be more important?

The problem is I really, really do have some sort of dyslexia regarding electricity. I don't have a technical aptitude like so many here and electrical theory has always been extremely hard for me to grasp. So many are throwing out terminology and calculations that leave my head spinning. As well, since some of the contributions may be more or less informed or correct, I'm not in a position to just know: "oh..what THAT guy just said is the right answer."

I asked for it. But really grasping the answer beyond "it doesn't matter what you buy" isn't easy, unfortunately.

Thanks for your replies - I do have confidence that you know what you are talking about. My understanding is the problem.

It's a real hassle cabling my system so I wanted to do it once and do it right. But I guess I won't sweat the details too much.
Balanced XLR's are pretty resistant to picking up noise. I tested some long lengths once by wrapping them few turns around a large PC switching power supply and running the PC on loop doing intense video processing. Nothing above the noise floor of -100 db on the ADC I had connected to them.

Did the same with RCA's and you got some audible noise with some unshielded cables, and less, but some visible in measurements even with coaxial cables. Un-looped and moved away 6 inches and all noise dropped below the noise floor of my gear.

So, don't run different cables parallel to each other if you can manage it. Separating them even 3 inches will probably work fine. If possible cross cables at 90 degrees. Don't put them directly on power bricks, but even a few inches distance is probably fine. With your rather short lengths it isn't going to be much of a problem and you won't have excess cable to route too many ways other than where you need it. In case you are wondering, no getting longer ones to be able to have more routing options isn't helpful.

In short, get the good Mogami, or Belden coaxial for RCA and there just isn't anything better. For XLR get good connectors from Neutrik or Amphenol with either of the good star quad cables from Mogami or Canare where once again there just isn't anything better. Oh, and the Audioblast you first mentioned is good cable. I've got a couple pairs I use.

I understand if you don't know, you just don't know. Quite correctly you don't then know how to know if advice you get is any good. I have plenty of areas in my life where that is where I am.

So if you have more specific questions ask. I'll try and explain if I can. Others here know more than me, and may explain better than I can.
 
OP
MattHooper

MattHooper

Major Contributor
Joined
Jan 27, 2019
Messages
4,472
Likes
7,153
Balanced XLR's are pretty resistant to picking up noise. I tested some long lengths once by wrapping them few turns around a large PC switching power supply and running the PC on loop doing intense video processing. Nothing above the noise floor of -100 db on the ADC I had connected to them.

Did the same with RCA's and you got some audible noise with some unshielded cables, and less, but some visible in measurements even with coaxial cables. Un-looped and moved away 6 inches and all noise dropped below the noise floor of my gear.

So, don't run different cables parallel to each other if you can manage it. Separating them even 3 inches will probably work fine. If possible cross cables at 90 degrees. Don't put them directly on power bricks, but even a few inches distance is probably fine. With your rather short lengths it isn't going to be much of a problem and you won't have excess cable to route too many ways other than where you need it. In case you are wondering, no getting longer ones to be able to have more routing options isn't helpful.

In short, get the good Mogami, or Belden coaxial for RCA and there just isn't anything better. For XLR get good connectors from Neutrik or Amphenol with either of the good star quad cables from Mogami or Canare where once again there just isn't anything better. Oh, and the Audioblast you first mentioned is good cable. I've got a couple pairs I use.

I understand if you don't know, you just don't know. Quite correctly you don't then know how to know if advice you get is any good. I have plenty of areas in my life where that is where I am.

So if you have more specific questions ask. I'll try and explain if I can. Others here know more than me, and may explain better than I can.

Thanks. I think you've given me enough to go on!

I do know enough not to run audio (and video) cables parallel with power cables, and to generally keep them away. Though specific distances at which it is "still close but ok" are more of a mystery. But I get the idea from what you wrote. Cheers!

The "cable risers" crowd would have a fit looking at my speaker cabling. It's Belden 10 awg (long run between rooms) and I have it buried in the shag rug behind my speakers so they are invisible. I'll never have a truly "black" noise floor like the tweaky cable-philes. ;-)
 

restorer-john

Grand Contributor
Forum Donor
Joined
Mar 1, 2018
Messages
10,392
Likes
29,989
Location
Gold Coast, Queensland, Australia
Just the simple act of putting a DAC on the left or right side of a power amplifier can make a difference as can the order (if you stack) components. Induced noise and hum can skyrocket. Back in the analogue days, with cassette/open reel recording, much time was spent carefully arranging the gear to reduce or eliminate hum/buzz (radiated). Just moving a preamplifier to one side or the other could make all the difference.

The basic rules haven't changed:
Keep low level gear away from high current gear and experiment with orientation. Consider where the low level high gain parts of circuitry are in a box and keep them physically away from power supplies, transformers etc. All the balanced connections in the world won't help you one iota, if the issues originate inside the unit itself.
Use decent quality, full shield cables, wired correctly (no weird audiophile wiring) with quality plugs.
Keep runs short, but no so short they are unusable or plain annoying.
Don't worry about speaker and signal cables lying alongside each other- that's just going too far. As for 90 degree cables- that's just silly stuff. Look at a studio's wiring, or a professional install in a concert hall, everything runs parallel- balanced of not.
Don't spend a fortune. Mogami, Canare and Amphenol, Switchcraft, Neutrik.
 
Last edited:
Top Bottom