Recommendation of in wall AC cable

DaveC · Oct 16, 2017

sbnx said:
Dave, you seem to know quite a bit on the subject. I agree that two parallel wires wound to make a solenoid carrying the same current but in opposite directions has an inductance of zero. Have you considered what happens when the return current is out of phase with the input current as will most definitely be the case on the output of an amplifier. The time averaged magnetic field will still be zero but within any given cycle there will definitely be inductance because at any instant in time the two magnetic fields don't cancel each other.

I'm definitely not an expert!

I think you'd have to investigate the specific geometries of the cable and the coil in question, and results may vary quite a bit from case to case... as does speaker cable performance in different systems. I should have been more clear that the coiling of a cable isn't the same as a coiling a single wire, it won't create inductance if the pair's magnetic fields cancel.

Speedskater · Oct 17, 2017

sbnx said:
Dave, you seem to know quite a bit on the subject. I agree that two parallel wires wound to make a solenoid carrying the same current but in opposite directions has an inductance of zero.

While it may be low (depending on the construction of the cable) it's never zero. Most of the opposite fields will cancel at a distance of about 10 times the spacing of the conductors.

Have you considered what happens when the return current is out of phase with the input current as will most definitely be the case on the output of an amplifier.

The output cable and the input cable are two different cables, so they don't impact each other's field.

The time averaged magnetic field will still be zero but within any given cycle there will definitely be inductance because at any instant in time the two magnetic fields don't cancel each other.

This is not what happens in a single cable.

Empirical Audio · Oct 17, 2017

Here is what I did, and it seems to perform well:

1) run plastic conduit to plastic boxes - you don't want the EM fields of the wires to be interrupted.
2) use 12 or 10 AWG THHN loose wires, Black, White and Green
3) twist together the black and white wires with a drill
4) pull through the conduit along with the loose green wire.

This gets you low inductance power feed.

Steve N.
Empirical Audio

Speedskater · Oct 17, 2017

Empirical Audio said:
Here is what I did, and it seems to perform well:
1) run plastic conduit to plastic boxes

This is good, but steel boxes and conduit (flexible or ridge) are also good and sometimes required.

- you don't want the EM fields of the wires to be interrupted.

That does not make any sense.

2) use 12 or 10 AWG THHN loose wires, Black, White and Green
3) twist together the black and white wires with a drill
4) pull through the conduit along with the loose green wire.

This method is very good.

This gets you low inductance power feed.

Very little affect on the inductance. But the twisting of the B & W does reduce what Bill Whitlock calls the 'Conduit Transformer' problem.

Steve N.
Empirical Audio

sbnx · Oct 17, 2017

Speedskater said:
While it may be low (depending on the construction of the cable) it's never zero. Most of the opposite fields will cancel at a distance of about 10 times the spacing of the conductors.

The output cable and the input cable are two different cables, so they don't impact each other's field.

This is not what happens in a single cable.

I agree that the inductance is non-zero due to the very small offset in the two conductors (e.g. Romex) even in the steady state case but it is pretty small. If you get something like JPS Labs In-wall AC then the conductors are actually twisted inside the jacket so there really isn't an offset between the conductors.

The fact that they are two separate wires each carrying current means that each has its own magnetic field. And as the magnetic field of each is a vector then they do interact with one another. if one is carrying current to the left and the other carrying the same current to the right then the magnetic fields will cancel. between the wires. So to first order if you wind ROMEX to make a coil then there would be zero magnetic field inside the coil and thus no inductance. However, Since the output AC current from an amplifier (for example) would be out of phase with the input current then during any given cycle there will be magnetic fields in the coil and thus the inductance will vary with time but over several cycles will still average to zero.

Agree with the statement that for a single wire (cable) you have the simple solenoid inductor.

All of this stuff is really small and probably insignificant. But we audiophiles tend to deal with 3rd and 4th order effects and tend to be OCD about every detail that could possibly matter.

Audiophile Neuroscience · Oct 17, 2017

I recently went through the process of adding dedicated AC power to my music room.I spent weeks reading Henry Ott and Bill Whitlock and Keith Armstrong and endless forum posts.

While controversies abound among audiophiles I expected a pretty straight forward answer on installing AC power for audio, so was a bit surprised that I didnt really find one. Also, my experience of domestic electricians (YMMV) was that they had little concept of why anything special was required.

I contracted an EE. I couldn't find one with audiophile background but he had experience in broadcast studios and medical facilities. I sourced VSD cable with braid and foil screen. We installed a subpanel and separate dedicated circuits and "technical" earth.The technical earth has its own ground stake and was bonded to neutral at the main panel as is required by code in Australia (and I believe I have read for USA ??). Main surge protection was at the mains panel using an industrial type device that supposed to somehow reject AC harmonics. Additional rfi/emi filter and rcd's at the sub panel. An optional "clamp" could be placed between the bonding between technical earth circuit and neutral for greater lightning protection and possibly additional prevention of retrograde noise.

All of this is just my uneducated understanding - my main point is suggesting to consult an experienced EE (and then hope for the best). For me, when it comes to electricity, get a qualified professional.

Cheers
David

Empirical Audio · Oct 17, 2017

Speedskater said:
This is good, but steel boxes and conduit (flexible or ridge) are also good and sometimes required.

That does not make any sense.

To an electrical engineer or physicist, it makes perfect sense.

Very little affect on the inductance. But the twisting of the B & W does reduce what Bill Whitlock calls the 'Conduit Transformer' problem.

It reduces inductance by mutual coupling. It works in speaker cables, power cables and in the wall wiring. I've simulated and measured the effect. Cables that are built like this have more accurate transient behavior.

Steve N.
Empirical Audio

CKKeung · Oct 17, 2017

In Hong Kong many audiophiles think that the Gigawatt LC-Y Mk3 in-wall cable is the best, after comparing it to other in-wall cables such as JPS ... etc
http://www.gigawatt.eu/produkt/in-wall-cable-gigawatt-lc-y-3x4-mk3/

Audiophile Neuroscience · Oct 17, 2017

Empirical Audio said:
To an electrical engineer or physicist, it makes perfect sense.

It reduces inductance by mutual coupling. It works in speaker cables, power cables and in the wall wiring. I've simulated and measured the effect. Cables that are built like this have more accurate transient behavior.

Steve N.
Empirical Audio

Bill Whitlock often advocates twisted pairs (cable that is

. What about starquad ?

Bill Whitlock ,

The matching of magnetic coupling can be improved by twisting the balanced pair, averaging their physical distance to the field source. Be sure all balanced line pairs are twisted. Twisting makes shielded or unshielded balanced pair lines nearly immune to magnetic fields and makes unshielded balanced lines nearly immune to electric fields. This is especially important in low level microphone circuits. Remember that wiring at terminal or punch-down blocks and inside XLR connectors is vulnerable because the twisting is opened up, effectively creating magnetic pickup loops. In magnetically hostile environments, consider “star-quad” microphone cable — it improves immunity to magnetic fields by about 40 dB compared to standard shielded twisted pair cable.

Empirical Audio · Oct 18, 2017

Audiophile Neuroscience said:
Bill Whitlock often advocates twisted pairs (cable that is. What about starquad ?

Bill Whitlock ,

Any geometry that puts opposite direction currents in close proximity lowers inductance. Putting same direction currents in close proximity likewise adds inductance.

Steve N.

Lee · Oct 18, 2017

I had very good luck with 10 gauge Romex. I have heard JPS is better but I have no experience with it.

Speedskater · Oct 19, 2017

Empirical Audio said:
Any geometry that puts opposite direction currents in close proximity lowers inductance.....Steve N.

Yes, exactly! So connecting the diagonal conductors in a Star-Quad to the same terminal lowers the loop inductance.

Putting same direction currents in close proximity likewise adds inductance.

The two conductors will sum as one and make calculating the loop inductance difficult.

engadin · May 14, 2022

Furutech Ft-Sws R Ncf wall outlets will unfortunately not work with the recommended above Gigawatt cable.

Gigawatt is 3 x 4mm, Furutech L and N are up to 5mm, but GND will only take 2.8mm. Damn.

CKKeung · May 14, 2022

For use with Furutech power-plugs, IECs and wall receptacles :

FP-209-10 (R) / (G） | FURUTECH

FP-209-10(R): 10pcs/set<br /> FP-209-10(G): 20pcs/set<br />

www.furutech.com

engadin · May 14, 2022

Thx a lot!
I think electricians will kill me if I give them orders to install wires with those spades in GND.
Maybe I should look for a decent 2.5mm in wall cable, as the distance from two Doepke FI and Gigawatt breakers to wall receptacles will be ca. 5m for front end and 5 and 10 m for power amps.

Don Reid · May 14, 2022

Other than knowing to use Romex I was ignorant of virtually everything discussed in this thread when I wired a new 20 amp circuit from my service panel to an outlet I installed behind my amplifier cabinet. That was twenty or twenty-five years ago. It is reliable, quiet and trouble free.

microstrip · May 14, 2022

engadin said:
(...) I think electricians will kill me if I give them orders to install wires with those spades in GND. (...)

In fact I can't see the reason of using these intermediate spades and using a plug cover with a conductive outer casing looks strange.

engadin · May 15, 2022

Problem is, electricians normally use wall receptacles with simple push-the-wire-inside-contacts, they’ll frown upon those screw down contacts.

Would an additional spade lug be allowed with their VDE safety rules?
I don’t know.

Anyone familiar with this wire?

https://www.on-off-hifi.de/Produkte/hifi-tuning-netzkabel-ultimate-solidcore/ZNZ12867

Said to have enthused German Stereo mag editor Tom Frantzen to equip two listening rooms with this stuff.

ACHiPo · May 15, 2022

I used 10-3 Romex (which is twisted) and snipped off the extra red wire on each end. This was for a 20A dedicated audio circuit—~20’ from the panel to 1st amp outlet, 8’ to next amp outlet, and ~20’ to front end outlets. There was still quite a bit of noise (including faint AM radio) when I checked with a noise monitor a few years after installation, and 500A instantaneous current delivery—not much more than 12-2 code Romex. Resistance to ground was ~0.2 Ohm. Shunyata Hydra, Denali, and NR PCs cured the noise. My take aways: 10AWG Romex is a bitch to work with and Shunyata NR works. If I do it over I’ll stick with 12-2.

Amir · Nov 7, 2022

Acrolink 4030

7N-PC4030Leggenda | Speaker Cable | Products | ACROLINK

An ACROLINK is a cable maker with the true 6N Cu which caught an analysis value guarantee.

www.acrolink.jp

Recommendation of in wall AC cable

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Furutech Ft-Sws R Ncf wall outlets will unfortunately not work with the recommended above Gigawatt cable.​

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Furutech Ft-Sws R Ncf wall outlets will unfortunately not work with the recommended above Gigawatt cable.