As another said, the insulation thickness will determine the inductance of the pair. Really thin insulation can get cylindrical wires down to about 150 nH per foot. Really thick, the value goes over 200 nH per foot.
Thank you John.
Absolutely correct.
No, same equations, just more difficult. For this app, just measure the capacitance and inductance per foot, Z = sqr(L/C). If you use multiple pairs, consider the impedance as the wires paralleled. This works well as long as the pairs are independently twisted. A quadstar cable is the most number of conductors that can be twisted together while maintaining magnetic orthogonality, it will have about half the impedance, or 50 to 75 ohms. A cat5e with the four combined solids and stripes will have 25 ohms.
Edit: when measuring a cable's L and C, do a sanity check using the equation L(nH/ft)C(pf/ft) = 1034 EDC. If you get a value of EDC that is less than 1, you've made a testing error, most likely inductance. You should get a value between 3 and absolute maximum 10 if the conductors are really far apart. And the cable prop velocity will be Vc/sqr(EDC), hence the can't be less than 1 thing...no superluminal signals here.
The only thing I'd mention here is be wary of wirewound and NI resistors. While an NI in theory is bifilar and non inductive, it still has a settling time due to the actual length of the element. I've no idea how that would affect frequencies under a gig..
It dampens out the rf stuff. It may increase phase margin of the amp, if the amp is a hot one.
Agreed.
Excellent work. thank you. I loved the baselining at the end..and the labels on the first three. The interesting thing to note is the interleaving of dip frequencies between load>z and load<z.
edit: I missed the longer length of cable on the bottom, I thought it was a frequency change due to opposite reflection coefficient...kept my error in the post, just pinked it.
Excellent suggestion.
You guys are awesome..made my day.
jn
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Instead of reading math, think why length is eliminated out of the equation. (L/L, CI is also named surge impedance)
(to pad PMA's line, it's been common practice to some for a couple of decades)
jn Thank you.
I think you should un-pink that sentense. See 2.4m/10 Ohm and 2.4m/200 Ohm. Comparable depth of notches but at different frequencies (this too to be explored).
As for an article, I would be honored but Jan wouldn’t be.
He does well keeping the standards of his magazine high.
There are many prohibiting reasons for not thinking over an article, the main one is that I don’t master the issue, I am studying it (and it shows
).Between you and me, why don’t you…?
George
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Ah, I see it now. My bad.. Sounds like that drill seargent phrase..
edit: the interleaving resonance frequencies caused by the changed reflection coefficient sign is consistent with what I recall.
Which is why I recommended you write one.
Perhaps a collaboration between several? So many here bring so much to the table.Between you and me, why don’t you…?
George
jn
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There are many prohibiting reasons for not thinking over an article, the main one is that I don’t master the issue, I am studying it (and it shows
At the point that you think you're a master, that's evidence that you're not. I'd love to see an article like that and I think Jan would be delighted to publish it.
Interesting information.
May I ask what book it's from?
And sorry if any of my ******* prior comments came through as I confused you with someone else. (thanks moderators)
PS do you honestly back the assertions of Bybee and his quantum whatevers?
Sorry George I confused persons there and I appreciate you deleting my comment.
It is important to study the 'advantages' of Teflon vs cheaper plastics to actually make an informed decision. Most big labs use both Teflon wire and caps in LARGE quantities. They DO have the money, but that is not the only reason that they use Teflon to such a high proportion, compared to other insulators.
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I've sure noticed a HUGE improvement going active DSP bi/tri amping.
Is this all phase related because when I hear a Danley synergy I felt the improvements were also similar.
Bare with me as I'm no EE.
I dunno what it is but it's something I can hear and I've noticed a similar psycho-acoustic affect between an LR2 and LR4.
Perhaps it's the full period time delay inherent is 360 LR4?
One big lab doesn't. Teflon tends to creep too much, has bad radiation resistance, and doesn't retain it's flexibility at 4.5K.
However, we do have roughly 1,300 power supplies with single digit ppm stability that we designed in house and farmed the assembly out, using some "horrific" D/A stuff...when I get a chance, I'll ask the designers what kind of caps they used for the high resolution analog stuff.
jn
How does it make reference to characteristic impedance of speaker cable?
How is that resistive zobel affecting the upstream amplifier's performance?
How does this affect Z?
Z is minimum safe load impedance right?
Bare with me I'm an amateur with high school physics and no formal EE education.
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