RCA Versus XLR Inputs/outputs convention

[Ron Resnick]

What is the reason that RCA inputs and outputs on components are all female (with the interconnect connectors having to be male at both ends), yet XLR inputs on components are female and XLR outputs on components are male (with the XLR interconnect connectors having to be male at one end and female at the other end)?

What is the underlying reason for this difference in convention?

 

[DaveC]

Good question... My guess is for 2 reasons, harder to confuse ins and outs on the backs of components, and if the cables are directional they won't get installed backwards.

 

[Ron Resnick]

Good question... My guess is for 2 reasons, harder to confuse ins and outs on the backs of components, and if the cables are directional they won't get installed backwards.

Both of those reasons make sense. Except I thought pro audio people did not believe in cable directionality?

 

[microstrip]

What is the reason that RCA inputs and outputs on components are all female (with the interconnect connectors having to be male at both ends), yet XLR inputs on components are female and XLR outputs on components are male (with the XLR interconnect connectors having to be male at one end and female at the other end)?

What is the underlying reason for this difference in convention?

IMHO a panel male RCA connector would be fragile and inconvenient to use. Besides the signal pin would be easily accessible and work like a small antenna.

Female XLR's have a longer pin 1 (ground) and make the ground connection before the signal pins - a very nice characteristic.

 

[DaveC]

Both of those reasons make sense. Except I thought pro audio people did not believe in cable directionality?

Sometimes a shield might only be attached to pin1 at 1 end.

 

[Folsom]

They are done that way because it is harder to damage the jack in both cases. It is assuming the cables are cheaper.

 

[Ron Resnick]

Sometimes a shield might only be attached to pin1 at 1 end.

True!

 

[Speedskater]

The RCA interconnect started as a very low cost mono system. There was only one cable per unit. A male chassis mount would look strange and be easily damaged.

Before the XLR, there were other larger male/female interconnect systems. A pro setup can have many cables and it would have been bad news to plug a ribbon microphone into a line level output (especially because line level often was a lot hotter back then).

 

[Chops]

Sometimes a shield might only be attached to pin1 at 1 end.

This...

Also, they are male on one end and female on the other end so they can easily be linked and more importantly, locked together to make longer runs without adapters or a chance to pull apart.

 

[astrotoy]

Both of those reasons make sense. Except I thought pro audio people did not believe in cable directionality?

Ron, there is a very important direction for cables. Output goes to input, not to output. So having different connectors on balanced cables makes sure you don't connect output to output. You can mix them with RCA's.

Of course, pros make up for this by not marking cables left and right. Pro equipment that is 2 channel usually mark the channels 1 and 2 and they assume the convention is 1 is Left and 2 is Right. But cables can be used in multichannel configurations and are generally not marked L and R or 1,2,3,4 etc.

Larry