I don't think so. Provided that the inductive reactance is swamped by the resistance then the characteristic impedance will be frequency-dependent and contain a significant reactive component. To get to this state you simply have to assume that the insulation is sufficiently good that copper losses dominate over insulation losses, and the frequency is sufficiently low. Oh, and you also assume that the cable is not a superconductor.RNMarsh said:
This is all well and good, I still find airborne RFI/EMI more often a problem. I plan to try +-48V flooded lead acid batteries as my primary audio PS sometime this year. Anyone have any experience with deep cycle vs automotive batteries? I use deep cycle for solar since the plates are thicker and they recover from 50% discharge, this gives a higher series resistance but in either case this is extremely low.
I am leaning toward deep cycle because in this respect automotive batteries are a very special purpose device. They are intended to deliver a huge current briefly and be kept topped up the rest of the time. I would think a long listening session would be like leaving your headlights on all night.
I am leaning toward deep cycle because in this respect automotive batteries are a very special purpose device. They are intended to deliver a huge current briefly and be kept topped up the rest of the time. I would think a long listening session would be like leaving your headlights on all night.
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Funny thing, the same day Herb Chambers had Jay Leno's F1 in he had some guy's classic Bentley on the lot marked "Today only $50000 off" ($275,000 to $225,000). I guess in the boom time this stuff was funny. Anyway he let me test drive it big round WW1 airplane dials and all, it just wasn't me.
Yes, that's the in between solution. One just needs to find the marine batteries without the yachtclub markup.
I did a quick search of material about battery lifetime and condition diagnosis and determined that it is anything but simple. This was prompted by someone who approached me with the familiar song-and-dance ("with my great ideas and your technical expertise WE could make a lot of money together"). I wound up concluding that Cadex is the probable leader in the field of analysis, particularly for automotive batteries.
But I put the "collaborator" off, and after an hour or two a day for three days, and advising him on a data acquisition system with bundled software, I informed him that I wished him well --- and implied that any further communication or advice would be with the clock ticking 😀
I really like the AGM battery type and they are also available for marine use.
Kind of pricey but they do really seem to last longer.
Kind of pricey but they do really seem to last longer.
For marine use, flooded 2V cells still outlast AGM's by ~5 years, but they require a safety container. (i've had deep cycle batteries crack on a boat)
Powersafe gel cells => http://www.ecolutions.nl/en/wp-content/uploads/2011/10/Plaatsing_accus_large.jpg
Powersafe gel cells => http://www.ecolutions.nl/en/wp-content/uploads/2011/10/Plaatsing_accus_large.jpg
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Right now I'm sticking with the flooded cells, they are just so much less up front. I have one set going on 10 yrs. Cracking is usually from freezing at low charge, the freezing point goes up dramatically with state of charge.
NO, I made a mistake, it is probably 50 uH. Sorry about that. You could have HAD me, Scott. Keep sharp! '-)
Top Fuel AA class..... 0-100mph in .75 seconds. F1 0-60 = 2.5 seconds. Lingenfelter (street legal) C6 = F1. Bet Kawasaki Ninja ZX-14R has more. 😛
You sure, Wave? Rule of thumb, 7nH per cm of conductor in free space, I make it 15uH for that scenario ...
Frank
Let's check.
An externally hosted image should be here but it was not working when we last tested it.
For 20M of 2mm thick copper wire it is 39386.7389298843 nH
2 wires in a cable will give approximately 4 times more. 140 micro Henry.
My rule of dumb gives closer result.
Did I miss anything?
Here is online calculator: Inductance of a Straight Wire: A Calculator
Boy! This is great. We have 15uH, 50uH, 140uH and 150uH. Good thing you all dont do design work for a living.
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