3 conductor cable for guitar?

[WorkBench]

I am using Belden 9271 for all of my guitar and effects cabling, and it has 2 hots and a ground.  What is the opinions here on how to wire this up?  2 hots to tip, and ground both ends?  1 hot to tip and twist the other hot to ground on only one end?  Or on both ends?  Is there a trick to this?

[cpnyc23]

When I've used cable meant for balanced applications I've always snipped off the 2nd signal wire and used shrink wrap to make sure it doesn't lead to shorts. 

For the ground wire, I've just connected both ends to their respective ground lugs.  I've never fully understood the ground on one end only practice... not that I doubt it works, I just don't know how to apply it correctly. 

-chris

[brett]

Hi
I use both hots for signal. 
Because the hots are so close together, using one for ground might increase capacitance per metre, and limit cable length.  I don't know whether this happens in practice, though.

[dschwartz]

i use the 2 hots together, tah way their respective resistance are in parallel..

[Processaurus]

Yes, both hots for the signal, that way the cable is half as likely to break.  The semi-balanced idea (one hot for signal, the other for ground, and the shield connected on the downstream end) always seemed like a joke with the tiny gain one might get in noise performance when thrown in with something as noisy as guitar pickups.

[any]

I've seen so many threads on this specific subject and it was always more pleasurable intellectually than practically... 

Alledgedly, Pete Cornish builts his rigs using one hot, one ground and the second hot as a floating ground (just soldered at one end).
If it's used in the right direction (floating ground at receiving end) and with enough cable lenght in some of the bigger rigs,
it might actually prove to be quite effective.

[cpnyc23]

hmmm.... I might have to try rigging a few cables up to see if there is any noticeable difference.  My guess is that if you are using a Cornish rig, the difference in fidelity might be worth the extra solder.  Something tells me that in my already noisy rig in my living room, pulsing with TV noise, fluorescent lights on dimmers, etc. wouldn't benefit from the floating ground.

Only one way to find out I suppose.

-chris 

[earthtonesaudio]

Some rules about cable:
1. Every different type of cable has a characteristic impedence determined by its geometry. 
2. Optimal performance requires proper termination.
3. Arbitrarily switching the shield and conductor positions changes the geometry significantly.

Guitar cables are a different story.  These are the exceptions, respectively:
1. Guitar cable makers rarely list objective specs of any sort, let alone "esoteric" things like characteristic impedance.
2. This is never a concern in guitar effects, because audio signals are slow enough to make it not really matter.
3. You probably couldn't tell any difference unless you put the signal on the outside and the shield on the inside.


Also...
The capacitance between the inner conductors is probably quite low (a few picoFarads), and the resistance of the conductors is also probably quite low (a few Ohms).
But if you short the inner conductors together you might actually increase the capacitave losses, because there wouldn't be a "shadow" cast by the other conductor... but when it comes down to it, can you hear the diffrence of a picoFarad or two, or an Ohm or two?  Probably not.
Then on the other hand, the second conductor is most likely spiraled around your signal conductor, which leads to other possibilities...


My opinion is that the best choice is to do whatever makes it easier/more reliable/simpler to construct.  Then you can convince yourself that it sounds better too!

[brett]

Hi

The capacitance between the inner conductors is probably quite low (a few picoFarads)

Read anything about cables and you'll find important things about acapacitance.  (ie it is capacitance that limits effective cable length, because long cables have so much capacitance they filter out highs.)  Of course, it you use a buffer close to the guitar, the cable quality (esp. capacitance per metre) is much, much less important.
cheers

[George Giblet]

I'll make stronger statements:

- *don't* connect the centres together, it doubles the capacitance.   It doesn't matter what cable it is.

- Connect it to the shield or leave it unconnected.

- Guitar cables are *never* terminated to the characteristic impedance.  Capacitance is the important parameter.

- The more capacitance your cable has the shorter the cable length can be before the cable capacitance affects the tone.  500pF is a reasonable target but results vary.  There's quite a few examples on the web showing this,

http://www.aqdi.com/cablecap.htm

There's also quite a few posts in the archives on the forum about this - not all correct.

- The Belden cable (with one centre connected) is about 72pF/m.  So a safe maximum length connected to the guitar would be about 7m.   This is a loose number because it depends on your guitar.

(- Some cables can produce microphonics when moved.)

[cpnyc23]

I had always assumed that the capacitance was increased when connecting both the 'hot' wires of a balanced cable in an unbalanced application... that's why I never did it.  I can see how, with certain guitars, that might be a good thing.  My 90's Les Paul (long gone now) had a problem of high-end harshness.  I found that thicker, crappier cable removed some of that.  Maybe using a balanced cable 'double wired' could have improved that without dulling the character like cheap cables did.

oh well...

-chris

[nooneknows]

I tried microphone cable with guitar in the past (balanced, umbalanced and semibalanced)  but I didn't like them. I use RG58 cable, there are different 'flavour' of it, one is not as stiff as the others, it's a killer cable, transparent durable and really cheap.