Stupid noob question regarding multimeter and resistance check
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RnB180

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So,

I was using a multimeter and set to reading to ac/ohm setting
and ran a test on an a xlr cable I made, with some gold alloy wire.



to test resistance the Id have to set it to ac/ohm right?
rx1 for a straight meter reading.

I received resistance of about

0.1-0.2 ohms or so.

audio techies, this question is for you, did I set it right for resistance?

and audio junkies how much resistance aside from "0" is exceptable for audio?
and are resistance levels of acceptance the same between xlr and rca cables for home theater?

Ive always used the meter for continuity, but Id really like to know if Im checking resistance properly.

Id like to know how well the gold alloy conducts
 
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RnB180

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28 views and no answer?

I was most certain that someone here would know the answer, we have geniuses, at least 90% of the people here are a lot more electronic inclined then me.

Ive never been too handy with numbers and techie stuff, Im actually the on the opposite spectrum as art is my thing.
 
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Garbz

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Well i think you set your meter right. The ideal wire has no resistance, but I belive 0.1ohm / foot or 0.1ohm / metre is acceptable for most audiophile grade cable.

Ideal cables should be the same for RCA and XLR although with XLR the difference is greatly reduced because of the balanced nature of the cable. As for home theater, wait did you say home theater? Any old 2 dollar cable will do.
 
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amb

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Many multimeters don't read very accurately down in the fraction of an ohm region. You can try shorting the two meter probe leads directly to each other in the same range and see if it still reads 0.1 ohm, or does it actually go to 0 ohms. Don't forget that the probe wires themselves have a small amount of resistance too.
 
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RnB180

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Quote:

Originally Posted by Garbz
Well i think you set your meter right. The ideal wire has no resistance, but I belive 0.1ohm / foot or 0.1ohm / metre is acceptable for most audiophile grade cable.

Ideal cables should be the same for RCA and XLR although with XLR the difference is greatly reduced because of the balanced nature of the cable. As for home theater, wait did you say home theater? Any old 2 dollar cable will do.




greatly reduced for xlr? what do you mean? the xlrs should be less then 0.1ohm per foot?

I was getting about .1-.2 on a length of 22" alomst 2'.

but I was using an old analog meter with a dying battery so it would sometimes give more resistance reading that actual since the current was dropping from the multimeter pin thingies.
 
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RnB180

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Quote:

Originally Posted by amb
Many multimeters don't read very accurately down in the fraction of an ohm region. You can try shorting the two meter probe leads directly to each other in the same range and see if it still reads 0.1 ohm, or does it actually go to 0 ohms. Don't forget that the probe wires themselves have a small amount of resistance too.



yea thats what I did, and set it to read "0" then I did the resistance test on the cable. and got the .1-.2 reading. but then the battery was dying, so the "0" reading would slip and and show slight resistance if I had the two probes touching each other directly.

but I think the .1-.2 reading was accurate. I did however notice that when the scale got more towards the end of the needle on the meter would struggle a tiny bit on the very last part of the reading, but it would eventually get to the .1-.2 reading.
 
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Quote:

Originally Posted by amb
Many multimeters don't read very accurately down in the fraction of an ohm region. You can try shorting the two meter probe leads directly to each other in the same range and see if it still reads 0.1 ohm, or does it actually go to 0 ohms. Don't forget that the probe wires themselves have a small amount of resistance too.



Yes, for that you need to use 4 wire resistance measurements. Heheh, quite a bit mroe expensive, though.

-Ed
 
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peranders

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The resistance in a rather short cable is pretty uninteresting, technically unless the wire is extremely thin maybe.

Why do you want to know this?

As pointed out 4-wire measurement is necessary. Pretty much of the resistance will be in the contacts!

Are you sure about the gold alloy? BTW: Gold is a worse conductor than copper but better than aluminium. Silver is the best, slightly better than copper.
 
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RnB180

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Quote:

Originally Posted by peranders
The resistance in a rather short cable is pretty uninteresting, technically unless the wire is extremely thin maybe.

Why do you want to know this?

As pointed out 4-wire measurement is necessary. Pretty much of the resistance will be in the contacts!

Are you sure about the gold alloy? BTW: Gold is a worse conductor than copper but better than aluminium. Silver is the best, slightly better than copper.




gold is only slightly under copper actually, and not by much, Im trying gold allow for something different. its condutvity is far above aluminum however. I like the sound of the wire, but just double checking what are exceptable levels of resistance.

so what resistance level would cause wire to get warm?
 
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Quote:

gold is only slightly under copper actually, and not by much, Im trying gold allow for something different. its condutvity is far above aluminum however.


Er.. actually, gold is more than slightly under copper, and it's certainly not far above aluminum. In fact, it's closer to aluminum than it is to copper.

Cu - 103% IACS (standard conductivity measurement, 103% means it's 103% as conductive as the standard)
Au - 73% IACS
Al - 64% IACS

If you're liking gold, why not try a mix of copper and aluminum?
 
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Aluminum and copper have the problem of tarnishing and corroding. An interesting reason to use silver or even gold is the resilience of the metal. People pay good money to have oxygen-free copper but it's probably much easier to get purer strands of wire using gold or silver.
 
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RnB180

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Quote:

Originally Posted by SDA
Er.. actually, gold is more than slightly under copper, and it's certainly not far above aluminum. In fact, it's closer to aluminum than it is to copper.

Cu - 103% IACS (standard conductivity measurement, 103% means it's 103% as conductive as the standard)
Au - 73% IACS
Al - 64% IACS

If you're liking gold, why not try a mix of copper and aluminum?



http://www.audioholics.com/techtips/...udiocables.php

audioholics says its smack dead in between copper and aluminum, its still more conductive that aluminum but less conductive then copper.

anyhow, I do indeed like the sound of the gold ally as its laid back and the bass response is incredible. back to the original question, is the margin of resistance acceptable for audio cable use. .1-.2 ohms.
 
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Garbz

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What do I mean about XLR?

XLR runs 3 wires. A ground connection to act as a return path / shield, a +ve signal, and the +ve signal inverted. THe three signals are kept in this state untill an opamp either sums them or they are fed into the drivers.

Any difference then between the +ve signal and the -ve signal will cancel out because it will be out of phase. So if noise is picked up on the cable it will be cancelled out when it gets to the drivers.

I've experienced first hand someone using a fully balanced system with unbalanced interconnects. 10$ worth of cable sounded incredible compared to the $600 Transparent interconnects that were being used.

Many of the problems such as noise, conductor issues, and importantly the ****** design of the RCA jacks mean nothing in a balanced system making the interconnects unimportant. This is why even the shinest gold RCA jacks on expensive equipment will be right next to stock standard balanced sockets. It simply doesn't matter to such an extent anymore.

That said the lower the impedance the better it is regardless.
 
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i simply adore how much sense balanced connections make. even in a relatively cheap system: technics 1200 -> ortofon scratch cartridge -> vestax mixer -> speakers, running a balanced connector for the last stop makes a world of difference compared to running a rca.
 
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Quote:

Originally Posted by RnB180
gold is only slightly under copper actually, and not by much, Im trying gold allow for something different. its condutvity is far above aluminum however. I like the sound of the wire, but just double checking what are exceptable levels of resistance.


I had to check but we are mixing resistivity and conductivity

Ag 15.87 10-9 Ohm/m
Cu 16.78 10-9 Ohm/m
Au 22 10-9 Ohm/m
Al 26.5 10-9 Ohm/m

An odd thing is that I always have seen 17,5 for copper and 16.2 for silver. Anyway, gold is slightly better concuctor than aluminium and silver is not that much better than copper.
 
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