[Escott1377]

I have read both answers - yes and no.

Belden makes a 12 AWG cable that is shielded, but I could not find a 10 AWG cable that is shielded.

I have ready to use a ferrite choke to help with reduce effects of EMI.

I am going to take a shot at making a few power cables.

Any help is appreciated.

[Letitroll98]

Shielding adds capacitance.  All my power cables are unshielded.

[barrows]

Simple answer is "no".  Power cables do not "require" shielding.  But whether or not shielding is a good idea for power cables will be system dependent.  Unfortunately, you will need to try both approaches to determine what will be best in your system.
A power cable can act as an antenna, and as an antenna it could both broadcast, and receive, airborne noise.  This may, or may not, be a problem in your system context.
Personally I prefer unshielded power cabling, but I do like to add RF damping (which some might consider shielding, but really is not) to some cables, especially those for digital components or other components which may generate high frequency noise (RF potential).

[Escott1377]

I plan just using the unshielded at 10 AWG.

If it's a problem, I can redirect.

I am having a discussion w/ someone that want to use carbon fiber on his cable build.

I think this will be shielding the cable and thus increase capacitance.

His thoughts are sine the shield will not be tied to the ground that this will not be true.

[Speedskater]

'barrows' answer is most excellent!
The added capacitance is trivial.
Because the two conductors are very close together, current noise is canceled at about a 2 inch distance.
This leaves the airborne noise antenna problem. Twisting the conductors helps and shielding helps.
'ground' has little to do with the solution, but most any shield should be connected to the chassis.

[Folsom]

If your power cables are making audible RF in the hearing spectrum, you probably have bigger issues barring a radio tower for a neighbor.

[One and a half]

Paranoia takes over and running power cables with some distance of signal leads is very difficult and in the back of my rats nest, power cables touch signal cables in a few places.
All my power cables are screened, with both ends terminated at the earthing pin. System is 230V.

[Speedskater]

It's not about audible RF, it's about how the RFI interference affects (effects?) a circuit once it sneaks into a component. A cell-phones 2GHz signal can be bad news for some hi-fi equipment.

Jim Brown being both the AES committee co-chair on EMI/RFI and a Ham radio operator writes on the problems:

"RFI, Ferrites, and Common Mode Chokes For Hams"
http://www.audiosystemsgroup.com/RFI-Ham.pdf

"RF Interference in Audio Systems"
http://www.audiosystemsgroup.com/AES-RFI-SF08.pdf

about 50 more Jim Brown papers:
http://www.audiosystemsgroup.com/publish.htm

[jeffreybehr]

It's not about audible RF, it's about how the RFI interference affects (effects?) a circuit...

Speed, the verb 'affect' means 'influences'; the verb 'effect' means cause.

[BobM]

Shielding may or may not be important for you, depends on where you live and what airborne grunge is broadcast in your area. But please ditch the ferrite - that only chokes out dynamics.

[jtwrace]

Personally I can't tell a flip of difference in my system.  However, I did make shielded for my dac.   

[Photon46]

Speed, the verb 'affect' means 'influences'; the verb 'effect' means cause.

Ok, if we're giving grammar lessons, 'effect' is generally a noun not a verb. No offense intended, these have got to be two of the most commonly confused words in the English language. 

[Speedskater]

The thing here is the interference affects the circuit, but to the listener it may be somewhat like a sound effect.

[jeffreybehr]

Ok, if we're giving grammar lessons, 'effect' is generally a noun not a verb. No offense intended, these have got to be two of the most commonly confused words in the English language. 

I agree; the reason I offered my note is that Speedskater indicated he/she didn't know which was correct.

I VERY seldom offer grammar/spelling/usage corrections online--WAY too many of the semiliterate are proud of their ignorance and wish to remain so.  Hence they resent anyone trying to educate them.

[Folsom]

The thing here is the interference affects the circuit, but to the listener it may be somewhat like a sound effect.

Not really...

The amount of noise to have an artifact literally means something is broken. I suppose it could sound like poor mastering, incorrectly used compression, etc... but noise never appears as something you could "put your finger on" in a properly working system.

Your earlier statement that you're hearing the affect of noise on your music is the best description. You don't know what the music sounds like without it, until it's gone. Even then you often have to listen for awhile and switch back to get a clear concept of what you were hearing because it's such a new form of understanding.

It's hard as ever loving hell to explain to a musician that there's changes to improve their gear, that can only make the type of sound they're making better... I'd venture to say maybe well above 90% can't conceptualize it. They literally won't even try because they assume it changes the type of sound, as to them the type of sound is the quality. I've found myself literally nearly banging my head on the wall wanting to yell at people over this because it's so infuriating that they're so god damn balless they won't even plug a guitar amp into a power conditioner... despite it being the most utterly amazing experience one can have with a power conditioner (ironically right after another group just did and loved it). Musicians are often some pretty unique snowflowers... and about as fragile as them.

[G Georgopoulos]

come on guys,the only way hum can get into a circuit is through a low level signal high gain circuit,these use regulated power supplies with very low hum ripple and seilded cables at the input(s) of the gain stages,there is no need to seild the power cable,just the signal cable of the gain stage usually the first one.

[Folsom]

come on guys,the only way hum can get into a circuit is through a low level signal high gain circuit,these use regulated power supplies with very low hum ripple and seilded cables at the input(s) of the gain stages,there is no need to seild the power cable,just the signal cable of the gain stage usually the first one.

Hum?

[Occam]

come on guys,the only way hum can get into a circuit is through a low level signal high gain circuit,these use regulated power supplies with very low hum ripple and seilded cables at the input(s) of the gain stages,there is no need to seild the power cable,just the signal cable of the gain stage usually the first one.

George - While the shielding thickness practically implemented on either ICs or power cords is quite effective against capacitivly coupled RFI noise, isn't it too thin to be effective against inductively coupled mains hum?



Skin depth vs Frequency

[Russell Dawkins]

come on guys,the only way hum can get into a circuit is through a low level signal high gain circuit,these use regulated power supplies with very low hum ripple and seilded cables at the input(s) of the gain stages,there is no need to seild the power cable,just the signal cable of the gain stage usually the first one.

Hmmm,
I thought you said you had left and made your last post...
http://www.audiocircle.com/index.php?topic=136527.msg1452003#msg1452003

[G Georgopoulos]

George - While the shielding thickness practically implemented on either ICs or power cords is quite effective against capacitivly coupled RFI noise, isn't it too thin to be effective against inductively coupled mains hum?



Skin depth vs Frequency

From experience I havent had any problem with inductive rfi coupling quite the opposite with capacitive coupling high frequancy rfi,to combat this i use nfb with low freq. response in the gain stages...