Balanced or unbalanced cables?

[poindy]

Hi folks,

 

need a few new cables for a small-ish PA set up and also to use for studio work.

 

Thinking that for keyboards and acoustic guitarts with pre-amps I should maybe be using balanced quarter inch jack cables. Have up to this point been using normal instrument cable (which I think is unbalanced) and thinking that's probably not right and a balanced cable would reject hum better and give a clearer signal allround. But to be honest I never thought about it before.

 

What do you think?

 

Thanks, Poindy

[bruce]

For most instruments, the outputs will be unbalanced, so using a balanced jack is pointless (and indeed may not work).

[Just Some Bloke]

... however, if you're worried about hum you may like to use a short unbalanced lead into a D.I. box, then a balanced lead from there to the desk. That should avoid any unpleasant gremlins.

 

[The DI box balances the signal for you, BTW]

[poindy]

... however, if you're worried about hum you may like to use a short unbalanced lead into a D.I. box, then a balanced lead from there to the desk. That should avoid any unpleasant gremlins.

 

[The DI box balances the signal for you, BTW]

 

Yep, makes sense. Presumably for big gigs that's why they use a di box even for acoustics with strong pre-amped signals because of the long cable runs/mulitcore and risk of hum. Sounds like I should be hapy with normal cable for small stuff maybe because pre-amps and keyboards output an unbalanced signal anyway... I think? Maybe

 

Thanks for your reply, p.

[Simon Lyall]

http://www.blue-room.org.uk/wiki/Balanced

 

that link might help a bit it with explaining the difference between balanced and unbalanced signals.

:)

 

simon

[paulears]

When you have a normal PA system in, the stage box has XLRs. So DI's are just the way you connect kit with phono's, 1/4" jacks etc into the level and balanced signal your PA is set up to deal with. The noise reduction properties are often not what you are using them for at all - after all, line level kit unbalanced is a fairly hot signal anyway - The reality is that reducing it to mic level, squirting it down a snake, then using desk gain to get it back up again is actually degrading the signal. A box full of DIs just make life easy. Some sources are problematic - my pet hate is acoustic guitars with internal pick-ups that always seem to hum and buzz - a DI does at least make it possible to get this in properly. Many keyboards, MD or CD players can be wired direct to an XLR with pins 1 and 3 shorted, with few ill efects - especially if they work from wall wart type power supplies - equally, this works amazingly badly on other bits of kit. I always have a few 1/4" to XLR unbalanced cables made up for these wierd possibilities.

[Tom R]

For £30 you may as well pick up a Bellringer DI and run your unbalanced jack from your instrument into it, so you can run your audio down a balanced XLR. This will, as you say, reduce the potential for noise and potentially give you a better signal. Remember that you will need phantom power or an external power supply for the DI.