Wiring Dual Female XLR to Single Male XLR for stereo signal

[nwns]

Hi All

As per title, I want to create some connectors to allow me to connect 2xXLR to one single XLR to pass stereo down one cable for IEMs. Am I going to see issues with Balanced to Unbalanced bearing in mind it's just for headphone monitoring on stage? Do I just wire the females from PIN 1 and Ground only and then one goes to Pin 1 to Pin 1 and the other Pin 1 to Pin 2? Shared ground.

Thanks

Pete

[Sam Spoons]

Where are you sending the signal from? And is it going to a headphone amp or straight to the cans?

[nwns]

From Aux sends to a Behringer PM1 box (passive)

[ef37a]

So Pete, you have left and right signals present on 2 XLRs and they are balanced* and you want to pass an unbalanced L/R signal down a 2 core cable? Not a problem AFAICS. Just take pin 2 as the hot signal for each channel and pin 1 as the common/shield. Make no connection to pin 3 from the source.

You might encounter a ground loop issue but that can be dealt with if it arises.

* "balanced" can be two 'oop' op amps or 'impedance' balanced and leaving pin 3 disse'd is the way to go. In the very unlikely event that the two sources are a floating transformer secondary you will need to tie pin 3 to screen.

Dave.

[nwns]

Thank you, I'll get out the soldering iron

[Sam Spoons]

The PM1 expects to see a stereo unbalanced feed from a headphone amp, it has no amplifier onboard. That may work driven from the aux's on the desk (I know it may 'cos I've tried it) but, depending on the desk you may find you have insufficient volume and you may also damage the aux output. What desk is it?

[shufflebeat]

What desk is it?

And does it have a headphone output?

[Wonks]

The PM1 is basically a stereo attenuator box, so you can set a high output signal from a headphone output and adjust it yourself locally. You'd typically use a TRS to XLR lead from a headphone output to the PM1.

The P1 may be the unit you are looking for, with two XLR inputs to take L&R Aux sends (or a single send in mono mode) and a battery to power the built-in headphone amp.

Or possibly the P2 with a single XLR/TRS input which accepts unbalanced stereo or balanced mono signals (mono/stereo switch is internal on this).

All basic details for the three models available on this Amazon page.

https://www.amazon.co.uk/BEHRINGER-POWE ... KXRMK?th=1

[nwns]

It's an XR18 and it only has a single headphone output. I already have the PM1s and didn't really want to buy more, probably should do I guess....

[shufflebeat]

The P2 set to stun... I mean stereo unbalanced should suffice, might even be possible to split the (same) mix signal for other users.

An adaptor (short TRSm¼"-XLRm lead) should enable you to use mic leads to connect your headphone output to P2.

Engage limiter on output. I do this by setting up an aux send with suitable limiting and solo-ing that output so it shows up on headphones.

[Mike Stranks]

A 'Dismal Jimmy' writes...

The OPs intended wiring was wrong - Pin 1 in an XLR is the Ground... but Dave's put him straight on that...

... But isn't wiring 2:1 generally considered a 'bad idea' unless you put in some buffering components to mitigate again against signal creep back into the source device?

These days I always use a specific buffering box designed cleanly to merge two inputs to one output.

[Wonks]

... But isn't wiring 2:1 generally considered a 'bad idea' unless you put in some buffering components to mitigate again against signal creep back into the source device?

Yes, but in this case the Behringer PM1's XLR is there to provide a locking connector for a TRS (headphone) output to the PM1's XLR input. So the XLR is set up for one side of an unbalanced stereo signal on pin 2 and the other side on pin 3, with pin 1 as a common ground. It is not set up to receive a single balanced input with a differential signal on pins 2 and 3.

[Mike Stranks]

... But isn't wiring 2:1 generally considered a 'bad idea' unless you put in some buffering components to mitigate again against signal creep back into the source device?

Yes, but in this case the Behringer PM1's XLR is there to provide a locking connector for a TRS (headphone) output to the PM1's XLR input. So the XLR is set up for one side of an unbalanced stereo signal on pin 2 and the other side on pin 3, with pin 1 as a common ground. It is not set up to receive a single balanced input with a differential signal on pins 2 and 3.

Thanks Wonks. Gotcha!

So... non-standard wiring... and a potential 'oops' for those who see an XLR socket and think, "Ah! So that must be..."