The only purpose served by the cross-connection scheme is to reduce the inductance, which of course increases the capacitance. I found some info on the cable, but not the effective guage.
50 ohms..Capacitance of 81 pf/meter...24.6 pf/foot.
Inductance of 61.5 nH per foot, dielectric constant of 1.46 (foamed or helix core.)
If the shield and core are resistively identical, cross will act as a 30 nH per foot conductor, if they are not identical, it can only go up.
If you use a twisted #14 pair, you'll have about 190 nH per foot, 6 of those in parallel would give roughly 31 nH per foot. Of course, you'd have to be very careful how you wire..use two colors.
Yes it will. I did not know the specifics on the cable, it's a big honker.
Cheers, John
If you don't cross-connect then you get the disadvantage of using thinnish conductors, but without the alleged advantage of reduced inductance and increased capacitance. You are essentially just using an expensive version of a normal twin speaker cable. It is not the coax cable which is special, but the wiring.
I have no idea whether it actually works, but it certainly can't work unless you build it correctly.
I have no idea whether it actually works, but it certainly can't work unless you build it correctly.
Coaxial cable Aircom Plus
It doesn't bode well according to the page above. It's written a bit strangely (it a german page so the translation might be a bit odd) but it seems that the shield resistance and the core conductor resistance are not the same (6,6 vs 3,8 ohms) which wouldn't surprise me considering how thick the core conductor is.
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Well folks some good news. I did some measuring on my Aircom Plus and things might not be that bad after all. The piece I have is 12 meters long so when measured with my cheapo multimeter resistance value ended up on 0.03 ohms both for the core conductor and the shield. I was a bit suspicious about the result so I did some calculating for the core conductor and ended up with the same result only far more accurate - 0.0351 ohms. That leads me to belive that that multimeter of mine might be quite a precise little thingy after all.
Anyhoo, since the final length of the cable will be 2 to 2.5 meters whatever the difference in resistance between the core conductor and the shield it is now it'll be 5-6 times smaller when the cable is finished. Therefore I think it's safe to say that the difference in resistance between the core conductor and the shield is none. To speak of that is equalling the inductance should be quite low, or so me thinks.
John?
Anyhoo, since the final length of the cable will be 2 to 2.5 meters whatever the difference in resistance between the core conductor and the shield it is now it'll be 5-6 times smaller when the cable is finished. Therefore I think it's safe to say that the difference in resistance between the core conductor and the shield is none. To speak of that is equalling the inductance should be quite low, or so me thinks.
John?
yes, increasing the copper cross-section reduces the cable resistance by a few milli-ohms.
Q1.) does a few milli-ohms matter?
Q2.) does spending extra money on those few milli-ohms make them better?
I think.
There's a thought.
I think that interconnects can, in these discussions, include any cable passing audio signals.
Well Sir, thank you very much. PaleRider?
I do agree with that allthou in this particular case it's more about decreasing the length that will reduce the cable resistance by factor of 5-6.
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Well I think we should leave that to the other 170,000 members to conclude. I personally am ready to agree upon whatever conclusion they come to
Cheers!
I will reluctantly observe their mandate if they tell me not to post any speaker cable discussion on this thread. But my opinion will remain the same, just different from theirs.
On this point I don't think there is a "wrong" opinion and thus no need to change just to fit in with the crowd. That's where hooligans get power ! We are not hooligans.
On this point I don't think there is a "wrong" opinion and thus no need to change just to fit in with the crowd. That's where hooligans get power ! We are not hooligans.
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But that has nothing to do with the cable! If you mean it must be able to drive the capacitance of the cable than I think my statement of low enough impedance covers that..
No.
The source must be capable of driving the load.
That is not a source impedance restriction.
set your output impedance at the source to any value from say 10r to 1k0.
If the source is limited to 10uApk output, it will be incapable of driving a 200pF cable in parallel to Ri=10k, in parallel to RF filter = 330pF at higher audio frequencies.
Increase the current capability to 100uApk and the source starts to become an audio source.
1mApk works but has no transient overhead capability.
10mApk would be a good all purpose source, irrespective of where you set Rs in that 10r to 1k0 range.
The source must be capable of driving the load.
That is not a source impedance restriction.
set your output impedance at the source to any value from say 10r to 1k0.
If the source is limited to 10uApk output, it will be incapable of driving a 200pF cable in parallel to Ri=10k, in parallel to RF filter = 330pF at higher audio frequencies.
Increase the current capability to 100uApk and the source starts to become an audio source.
1mApk works but has no transient overhead capability.
10mApk would be a good all purpose source, irrespective of where you set Rs in that 10r to 1k0 range.
You need both. Current driving ability avoids clipping into a resistive load, and slew rate limiting into a capacitive load. Low output impedance avoids non-linear distortion into a non-linear load, either resistive (amp input) or capacitive (cable capacitance), as well as reducing HF roll-off.
The core is close to #10awg. #10 has a per foot R of 1.08 milliohms.
The shield is (6.6/3.8)*1.08, or 1.87 milliohms per foot, that is close to #12awg.
That is incorrect. The absolute values are not important to how two different guage wires share current when they are paralleled. If a wire has double the resistance of it's mate, it will take half the current of the mate when they are paralleled. It is this relationship that determines how well the current distribution cancels the wire inductance for the cross connected configuration..
Only 170,000? Heck, I've disagreed with a lot more than that..
That is an incorrect statement.(edit: the first statement....I make no claims on the second..) Calculation of the ground loop resistivities caused by the shields and line cord safety ground show easily enough that changing the IC's will alter the ground loop. EMC stuff.Interconnect cables make no difference to the sound providing that the driving impedance is low enough for the cables capacitance not to effect matters, which it usually won't.
Try telling that to all the people who have been brain washed by the hifi magazines and dealers though!
And a third. EMC considerations of shield loop resistivity.
Cheers, John
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