Measured the Alpha Wire

[Mudcat]

Subsequent to my recent post on the measured LCR parameters of Carol 12 gauge 4 conductor cable, I measured a 6 foot section of Alpha Wire 85104CY. This is a 10awg 4 conductor shielded cable. Each conductor is 658 strands of 38 awg wire. And it is really expensive at $15/foot wholesale (I found what I was told was about 100 foot, but when measured turned out to be closer to 48 feet - no one to complain to because it was a garage sale and they moved, but still I only paid $25) .

I tested this cable three ways, and always the same two conductors. The first number will be the two conductors with the other two conductors open, the second number will be with the other two conductors shorted, and the third number - if any, will be with the outer jacket and shield removed and only the inner jacket covering the conductors.

Anyway the data you are all looking for. All results are per foot.

DCR = 0.0033 - 0.0033 (ohms)
RAC@100Hz = 0.0025 - 0.0022 (ohms)
RAC@120Hz = 0.0025 - 0.0022 (ohms)
RAC@1000Hz = 0.0022 - 0.0028 (ohms)
RAC@10000Hz = 0.0141 - 0.0146 (ohms)
Cp@100Hz = 45.65 - 45.4 - 31.3 (picofarads)
Cp@120Hz = 45.2 - 45.13 - 31 (picofarads)
Cp@1000Hz = 41.95 - 41.79 - 28.2 (picofarads)
Cp@10000Hz = 38.1 - 37.95 - 26.4 (picofarads)
Ls@100Hz = 0.24 - 0.259 (uH)
Ls@120Hz = 0.21 - 0.257 (uH)
Ls@1000Hz = 0.21 - 0.21 (uH)
Ls@10000Hz = 0.215 - 0.218 (uH)

Notice that I only measure the capacitance after I removed the shield. Also notice that the capacitance went way down after the shield was removed. So, is there an electrophysicist out there who can anlyze this data and explain why the capacitance droped after removing the shield when all else remained the same, and explain the minor differenced when the unused conductors were shorted oppposed to open?

 

[jneutron]

Subsequent to my recent post on the measured LCR parameters of Carol 12 gauge 4 conductor cable, I measured a 6 foot section of Alpha Wire 85104CY. This is a 10awg 4 conductor shielded cable. Each conductor is 658 strands of 38 awg wire. And it is really expensive at $15/foot wholesale (I found what I was told was about 100 foot, but when measured turned out to be closer to 48 feet - no one to complain to because it was a garage sale and they moved, but still I only paid $25) .

I tested this cable three ways, and always the same two conductors. The first number will be the two conductors with the other two conductors open, the second number will be with the other two conductors shorted, and the third number - if any, will be with the outer jacket and shield removed and only the inner jacket covering the conductors.

Anyway the data you are all looking for. All results are per foot.

DCR = 0.0033 - 0.0033 (ohms)
RAC@100Hz = 0.0025 - 0.0022 (ohms)
RAC@120Hz = 0.0025 - 0.0022 (ohms)
RAC@1000Hz = 0.0022 - 0.0028 (ohms)
RAC@10000Hz = 0.0141 - 0.0146 (ohms)
Cp@100Hz = 45.65 - 45.4 - 31.3 (picofarads)
Cp@120Hz = 45.2 - 45.13 - 31 (picofarads)
Cp@1000Hz = 41.95 - 41.79 - 28.2 (picofarads)
Cp@10000Hz = 38.1 - 37.95 - 26.4 (picofarads)
Ls@100Hz = 0.24 - 0.259 (uH)
Ls@120Hz = 0.21 - 0.257 (uH)
Ls@1000Hz = 0.21 - 0.21 (uH)
Ls@10000Hz = 0.215 - 0.218 (uH)

Notice that I only measure the capacitance after I removed the shield. Also notice that the capacitance went way down after the shield was removed. So, is there an electrophysicist out there who can anlyze this data and explain why the capacitance droped after removing the shield when all else remained the same, and explain the minor differenced when the unused conductors were shorted oppposed to open?

The shield is acting as a capacitor to each wire, so the wire to wire capacitance is paralleled by the wire to shield contribution.

My guess on the small diff in capacitance with others shorted, is it's so small, that test lead errors and meter capability are coming into play..the inductance, I'd guess the cable probably has geometric imbalance, just from the spiralling machine and insulation tolerances..Ideally, there'd be no inductive coupling, but wire forming ain't exactly ideal, and a 4 wire twist is not a stable geometry..3 is, as well as 3,4,5 and (marginally)6 around 1, depending on twist of the exterior wires.

In the user manual for the 885, they show 4 wire inductance setups, and how the shield currents are supposed to cancel..You're setup will typically have .1 to .2 uH errors just from that connection set..If you want to really be "a stickler" about resolution, that'd be the first place I'd look.

As for the small diff?? Geeze, you mechanical engineers....always gotta be nine digit accurate..Reminds me of a two headed puppeteer..(bet ya don't know where that comes from...)

Cheers, John

 

[Audioholics]

Not-so-obscure Larry Niven reference?

 

[Mudcat]

As for the small diff?? Geeze, you mechanical engineers....always gotta be nine digit accurate..Reminds me of a two headed puppeteer..(bet ya don't know where that comes from...)

Wrong, Wrong, Wrong! We always stop when

e^yxp=6.23x10^23$

Dang, you can't make nonsensical formulas here like you can in word

 

[Louis Wu]

Not-so-obscure Larry Niven reference?

Spoilsport. Go suck a bandersnatchi..

Cheers, John

 

[Chmeee/neutron]

Spoilsport. Go suck a bandersnatchi..

Cheers, John

For those not familiar with Niven, a bandersnachi is a really large slug-like (best of my recollection) beast, that is hunted for thrill..it is intelligent, and does not mind being hunted, under one condition...the odds of the human hunters are equal to that of the prey...half the hunters don't survive the hunt..

I couldn't edit the post to clear that up, so voila...

Cheers, John

 

[Mudcat]

I usually turn to my Paris Hilton video for fantasy, but to please John, I've given my system (go to Member Systems, and "My What A Nice Rack") a name

Mt. Lookatthat

 

[gil hamilton..]

I usually turn to my Paris Hilton video for fantasy, but to please John, I've given my system (go to Member Systems, and "My What A Nice Rack") a name

Mt. Lookatthat

Hey, Mudcat...

What's the inductance of that wire if you connect it +-+- as you rotate..iow, parallel 12 and 6 as positive, and 3 and 9 as negative..Saw that Q at CA, and wondered how the proximity couples the pairs.

Ummm, just Ls and Cp at 1Khz would be great, measured with the two pairs paralleled, and just an adjacent pair, ..

And, what is the conductor diameter, and the spacing of adjacent wires, like from 12 to 3..

Cheers, John

 

[Mudcat]

What's the inductance of that wire if you connect it +-+- as you rotate..iow, parallel 12 and 6 as positive, and 3 and 9 as negative.

I'll get back to you

Saw that Q at CA,

Uh? Are you asking about the Dissipation Factor, or Quality? If so, I'll get back to you. I'll assume that both of these are also a factor of length. Do you also ESR for the inductance?

and wondered how the proximity couples the pairs.

I'm still thinking about Paris Hilton

Ummm, just Ls and Cp at 1Khz would be great, measured with the two pairs paralleled, and just an adjacent pair

Thanks for making me work less

And, what is the conductor diameter, and the spacing of adjacent wires, like from 12 to 3

Conductor Diameter is 0.1525 inches (with insulation) minus 2x0.022 (insulation thickness) equals 0.1085. Solid 10 awg is 0.1019. Center to Center of adjacent conductors appears to be 0.1836 inches, but may only be 0.1525 (it's hard finding the center of a mangled wire)

 

[jneutron]

Uh? Are you asking about the Dissipation Factor, or Quality?)

Neither.."Saw that Q at CA" is geekspeak for " somebody over at the Cable Asylum had that Question..."

I'm still thinking about Paris Hilton

Hey, maybe she'd be impressed with your Mt. Lookatthat.(don't even go there)...but, with that rack, do you even have room for a bed??

Cheers, John

 

[Mudcat]

Well, now that it's been mentioned

How do the dissipation factor, quality, and ESR effect the capacitrive and inductive performance of a cable? Any takers.

Oh John, it's a big room. It use to have an entire studio setup. Lots of amps, monitors, mixers, lots and lots of blinking lights, buttons and knobs.