How to tell if mic cables are balanced?

Z

Zeroquag

New member
Through searching posts I read that if mixing dynamic with condenser mics under phantom power, you should use balanced cables.

I have some I bought recently I know are, but without being an electrician, how would I tell if older cables are balanced or not? I'm talking XLR to XLR mic cables. The ones I have all have three pins if that matters, and I can't tell the difference between the balanced and questionable ones.
 
Im not sure if an XLR cable CAN be unbalanced by itself.

If you have a multimeter, test that all 3 pins are connected to their respective
pins at the other end.

IE: test pin one on the male end with pin one on the female end etc. etc.

If all three match, the signal is balanced.
 
Well, technically, the cable itself isn't balanced or unbalanced. It is part of a system which is balanced, but the cable does have to be compatible with that system. 2 wires for the signal twisted together for better interference rejection and one shielded ground.

A balanced system means the two wires for the signal have matching impedance. This is usually done with isolating transformers on each end of the cable, but sometimes not.

As for the phantom power thing. It's important that the cables are xlr because 48 volts will be applied to both of the signal wires. If you use any other cable, you run the risk of applying 48 volts to only one side of your transducer and will probably ruin it.
 
Chili said:
A balanced system means the two wires for the signal have matching impedance. This is usually done with isolating transformers on each end of the cable, but sometimes not.

As for the phantom power thing. It's important that the cables are xlr because 48 volts will be applied to both of the signal wires. If you use any other cable, you run the risk of applying 48 volts to only one side of your transducer and will probably ruin it.
Click to expand...

minor quibble... a balanced sig has two lines one of which is inverted...160degrees out from the other... i wonder just what % uses trannies??? i suspect very low... applying 48V to one side will hurt only if the other side is grnded...
 
Thanks all! Seems from what I read here and around like any 3-pin XLR will allow a balanced signal, and mine do have two live and a ground, so I'll make that assumption.
 
What about XLR -> 1/4" cable? Can that be unbalanced?

I just bought a studio projects B1 and when I used my old cable (from an older dynamic mic) to plug it in, I got no sound (using phantom power, of course). I'm guessing that's because it's an unbalanced cable (XLR -> TS).

I'm heading to the store to get an XLR - XLR cable - that should do the trick.

Erik
 
Balanced cable uses 3 conductors. xlr has 3 conductors. Also, some 1/4" cables, also called TRS or "tip, ring, sleeve" cables are capable of carrying a balanced signal.

As far as your 1/4-xlr cable not working with your condenser mic, I believe most preamps only send phantom power through the xlr connector and not the 1/4" jack.
 
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