If using 2 conductor mic cable can you just do this ?

[Incubus]

I've been following the thread where semi-balancing is suggested.

Just wondering if I could wire my cable by just using the hot conductor as signal, sheild as ground and just not connect the second conductor ?

Any disadvantage to doing this.....noise...anything ?

[LyleCaldwell]

You'll just pay more for cable than you need to but it will work fine.

[BrianJ]

The cable will pass signal for sure, but it won't be anything near balanced. 

[Satch12879]

And why would you do that? You don't get any kind of benefit, unless that's the only cable you have around, but then again, you could just do the 2 conductor + sheild deal properly and be done with it.

[Incubus]

Here's why.

The cables I have are all mic cables.....2 conductors plus sheild....and I'm using them as guitar cables.

Up until now, I've always had it connected as the sheild was ground, and the 2 conductors soldered together at either end.

I recently saw a thread saying this is kinda crappy......high end rolls off too soon.

They suggested having the hot conductor connected to the tips at both ends. Then connect the other conductor to the sleeve of the jacks at either end. Lastly, connect the sheild to the sleeve of only one jack, and leave the sheild not connected at the other end. The cable is now directional, but sound quality is improved.

I tried this and it does work, but I don't like having the sheild not connected at one end.

So I was thinking why not have the hot conductor to tips at both ends. Then sheild to sleeves at both ends. Then just leave the other conductor not connected at both ends.

Since then, I saw on a different forum a post which I will paste here:



"OK...after doing some more research and talking to the techs at Rane (great people, thanks Chris!)...I'm going to re-evalute my own situtation and my post above.
Apparently, lifting the shield at one end of an unbalanced cable like what we are talking about above, is NOT going to really solve anything and WILL possibly bring RF problems into the picture.

The recommandation for 2 conductor + sheild for unbalanced, single-ended plugs/jacks:

+ tip: (first conductor)
- sleeve: (second conductor AND shield connected AT BOTH ENDS OF CABLE)

NO FLOATED SHEILDS.......that only helps BALANCED connections"



This is what I'll do to my cables now and then do some testing. It makes more sense than leaving a sheild floating anyway.

[DuncanM]

The cables I have are all mic cables.....2 conductors plus shield....and I'm using them as guitar cables.

Up until now, I've always had it connected as the shield was ground, and the 2 conductors soldered together at either end.

I recently saw a thread saying this is kinda crappy......high end rolls off too soon.

That'll be me I guess - yes, I tried it at Lyles suggestion and using a single conductor I could hear a subtle improvement in the very high end when using headphones and in isolation. Your cable may be different and the effect might be unnoticable through an amp...

"kinda crappy" is a bit of an overstatement - I didn't notice for years! But then again, I've only recently learned to listen critically.
Only one way of telling - try it and see if you can hear a difference for yourself. 

Not using the second conductor at all might even be a bit better - even less capacitance... I can't see any disadvantages, just cut the unused conductor back so it can't accidentally short the signal to the screen.

Personally, I also have a predjudice against connecting the shield at only one end.

[LyleCaldwell]

Disconnecting the shield at one end, when the shield is not serving as the negative connection, is actually much better practice.  Just like it's better to only have an enclosure connected to one ground point.  It's preferable to have the negative path separate from the shield - no signal flow through the shield.

[DuncanM]

Disconnecting the shield at one end, when the shield is not serving as the negative connection, is actually much better practice.  Just like it's better to only have an enclosure connected to one ground point.  It's preferable to have the negative path separate from the shield - no signal flow through the shield.

Well, I don't really understand the logic behind it but I've been wrong before so I guess I'll just have to go and try it....  .

[Processaurus]

Hi, leaving your second conductor unconnected and floating would be the noisiest option compared to the semi balanced arrangement or using both center conductors to carry the signal, or even connecting the second conductor to the sheild at both ends.  Leaving a long wire electrically floating makes it into an antenna, and then you'd have this antenna right next to the wire carrying your guitar signal. 

If you find yourself thinking about noise and capacitance from your cables alot, consider installing a buffer onboard your guitar.  This would make a noticeable difference that you could hear out of your amp, rather than just with the finest headphones in a quiet house. The lowered output impedance would drive your cable better (and make for less of a difference between using a cheap cable and nice cable), and you would have no problems with capacitive loading or noise.  Also if you put it before your volume control, (and use a lower value pot (25K for example)) then when you turn your volume knob down you won't lose high end, or have any other change in tonality.  The only downside to this is if you use a fuzz face type pedal, which works by loading down your pickups.

Of coarse, remember Jimi with his big floppy coily cords, which are the supposedly the shittiest sounding cords you can use.  He managed to sound alright.

[SolderBoy]

He managed to sound alright

In most cases, an hour with the metronome will improve your tone a lot more than an hour with the soldering iron!   


If you twist two (insulated) wires together, you make a capacitor.  I would bet that a mic cable with one conductor connected to earth and one conductor as hot (reguardless of how the braid is connected), would have a much higher capacitance than if you used both conductors as your hot, and the braid as the earth.  This is because the two conductors are twisted together inside the cable. 

I've used mic cable for instrument cable in several different configurations, and whether you perceve a difference in tone and whether it actually matters in the mix... well you can decide.

Some cables make very strange noises.  I was at sound check a few years ago and my newly made guitar cables seemed to be very microphonic - they made a tapping sound when you wiggled them on the floor etc.  I started thinking about piezo-electric effect in high impedance circuits blah blah blah.

Then I realized that all the mics were live, the foldback up, and I was alone on a wooden stage in an old hall.  The whole floor was like a percussion instrument!   

[DuncanM]

Leaving a long wire electrically floating makes it into an antenna, and then you'd have this antenna right next to the wire carrying your guitar signal. 

I thought an antenna had to be earthed at one end?
But surely the induced voltage in an unused conductor would be very small and the coupling with the signal conductor would be very small as well, so as to make the interfering signal very, very small. (?)

I would bet that a mic cable with one conductor connected to earth and one conductor as hot (reguardless of how the braid is connected), would have a much higher capacitance than if you used both conductors as your hot, and the braid as the earth.  This is because the two conductors are twisted together inside the cable. 

I don't think that in MY mic cable the condutors ARE twisted together...
However,
I do think that capacitance between core and screen is larger than capacitance between core and core - you have a double thickness of insulation between cores..
If you have both cores joined at both ends, the whole of the screen is acting as the "other" plate of the capacitor.
If you use one core, the screen is only adjacent with the core over (about) 60% of its surface and this would reduce the effective area of the "other" plate (the screen) - and so the capacitance.

Or I may be wrong - but that's my rationale...

[SolderBoy]

Hmm... actually, your rationale sounds a whole lot more rational than my rationale....

Yes, I think you are right!


Its late at night here... 

Well that's my excuse and I'm sticking to it (irrationally).

[LyleCaldwell]

It's still relatively minor differences we're quabbling over.  Good XLR cable has a much lower capacitance per foot compared to instrument cable.  Unless you're using really really long runs of cable, the audible differences should be slight to meaningless, aside from noise issues (separating the shield from the ground can be much much quieter).

[SolderBoy]

Not to mention the roll-off that guitar speakers have...

[scaesic]

you could add in a couple of invertors, and have your guitars wired to take balanced signal.

[gtrmac]

Is "semi-balanced" anything like a little bit pregnant?