Liquid-in-the-tube Headphone Cable (using seawater?)
Nov 28, 2008 at 3:05 PM Thread Starter Post #1 of 21

cotdt

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What kind of liquid has good electrical conductivity? I'm thinking of processing seawater to increase its conductivity.

I don't want to use mercury, because I want the liquid to be transparent. It will be in a tube and used as a headphone cable. Resistance of cable is not really an issue, but something like 10 to 100 ohms would be good. Resistance increases the electrical Q of the headphone drivers and thus improves the bass response.

I'm thinking of using genuine San Diego seawater at this point. What do you guys think? This will be for a Sennheiser.
 
Nov 28, 2008 at 4:39 PM Post #3 of 21

cotdt

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Quote:

Originally Posted by Tridacnid /img/forum/go_quote.gif
I've had the same idea, but I remember reading that saltwater is a much worse conducter than one realises.


A saturated saltwater solution should have pretty low resistance (23 conductivity units), and should work. Were you using DC or AC? DC will use up the saltwater solution but AC should work fine, so it should work for carrying audio signals.

You can use a thicker water tube to lower the resistance. Resistance R is given by the specific resistance * Area / Length. That is R=rho* A/L or in terms of conductance K and specific conductance kappa K = 1/R = kappa *L/A. But in a headphone cable some resistance is desirable, such that some cables actually have resistors put inside.

The movement of electrons of an ionic solution is fundamentally different than in a metal, since instead of freely moving electrons, it is the ions themselves that carry the charge. Hence I am expecting some interesting sonics here.
 
Nov 28, 2008 at 4:39 PM Post #4 of 21

JamesL

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Hm.. Reminds me of a 5th grade science project.

I know NaCl is enough to make a light bulb light...
Lemon juice comes to mind too for some reason.

I remember someone talking about how even wet noodles would work, and i was seriously considering experimenting. =p
 
Nov 28, 2008 at 6:49 PM Post #5 of 21

NelsonVandal

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All hi-fi products have to be burned in to sound good. You should know that. How can you possibly burn in water. It'll vaporize, and you'll have nothing but two empty tubes.
 
Nov 28, 2008 at 6:54 PM Post #6 of 21

Uncle Erik

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Liquid? Try mercury.
evil_smiley.gif
 
Nov 28, 2008 at 11:22 PM Post #8 of 21

UglyJoe

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cotdt,

look up the transference of various ions to get a better idea. You're looking for and ion pair that diffuses quickly through the solution, but also one where the cation and anion have roughly the same transference, in order to achieve the same flux on anodic and cathodic voltage swings.

I'm not sure how this would work, as ionic movement in solution is much MUCH slower than electron movement in a conductor; be warned that the cable will probably have a very high capacitance... Well, I'm used to dealing with non-aqueous solution, and water is extremely conductive compared to those, but still my gut instinct is that this won't work well as anything other than a conversational piece... but it would be cool!

EDIT: Also, you must be very careful that you don't get some redox chemistry going on in the wire... even a couple of volts swing plus/minus (if much of that voltage is dropped across the relatively highly resistive cable) could cause reduction of dissolved oxygen; corrosion of the connectors, maybe even hydrolysis of water... because music is fairly high frequency I think you'd be okay, but it's something to think about.
 
Nov 29, 2008 at 2:15 AM Post #10 of 21

Jackalope

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it's been done? sorta...

Teo Audio: Liquid Cable

Their site doesn't have much in the way of detail, but maybe you could email them and ask some questions?


actually, there iare some details. click on the msds it lists gallium, indium, and tin, in varying concentrations to make a "silver liquid", could be a little bit of help.
 
Nov 29, 2008 at 4:33 AM Post #11 of 21

rembrant

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Are you guys serious?
Lets take a minute and examine what would be the perfect cable if it existed.
1. Zero resistance
2. Zero inductance
3. Zero capacitance

Resistance and Inductance are directly related in more than on term.
1. The higher the resistance the greater the inductance.
2. The higher the resistance the bigger the conductor must be also raising inductance.

Knowing those two facts alone leads us to silver as a conductor. It has lower resistance and can be used in smaller diameter than copper for the same resistance, thus lowering inductance.

Capacitance comes from having two dis-similar materials in close proximity. Having a cable with multiple strands increases capacitance.

Now, knowing those things should tell you that the best you can do is to have a solid core silver conductor cable with a Teflon outer cover. Since there is no perfect cable, inductance will always be a problem. So, a shield around the outside of your cable connected to ground at the source end is a good idea.

There are a whole host of other factors like oxygen content and skin effect that can change the way a cable sounds. I wont dive onto those subjects here because I am not writing a thesis.

The point is? We strive for an accurately reproduced signal. Not one that is colored or flavored in any kind of way. Though you may like what you hear, that doesn't mean it's what was recorded in any since of the word.

If you insist that liquid cables are what you need. Then I have a bridge in Nevada I would like to sell you. I swear your music will sound mo betta.

beerchug.gif
 
Nov 29, 2008 at 4:43 AM Post #13 of 21

Pars

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Quote:

Originally Posted by rembrant /img/forum/go_quote.gif
Are you guys serious?
Lets take a minute and examine what would be the perfect cable if it existed.
1. Zero resistance
2. Zero inductance
3. Zero capacitance



Quote:

Originally Posted by MisterX /img/forum/go_quote.gif
You forgot non toxic.
icon10.gif



You also forgot doesn't leak all over our equipment and short it out
eek.gif
 
Nov 29, 2008 at 8:19 AM Post #14 of 21

Navyblue

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Why does it have to be seawater? I'd imagine some sort of synthetic concentrated electrolyte solution would do better.

We know that conductivity is proportional to the ion concentration in a solution. Can we get more molar concentration with ion that has a low molecular weight? If so then hydrofluoric acid might be the molecule with the lowest molecular weight. We also know that temperature is proportional to solubility, so you want the conc. HF to be heated. We also know that pressure increases boiling point, so you want it to be in a pressurized tube.

The problem is how to get it not to dissolve your headphone and your amp, so may be mercury is safer
biggrin.gif
 
Nov 29, 2008 at 8:22 AM Post #15 of 21

Uncle Erik

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Quote:

Originally Posted by Navyblue /img/forum/go_quote.gif
The problem is how to get it not to dissolve your headphone and your amp, so may be mercury is safer
biggrin.gif



It would be a nice compliment to mercury vapor rectifier tubes, as well.
biggrin.gif


mv_rectifiers.jpg
 

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