I have need to connect 2 balanced outputs to a single stereo 1/4" for a headphone amp.
 
While I know to take the Hot from each output and connect to Tip/Ring as required and join the grounds together at the sleeve, what do I do with the "cold" from the balanced connections?
 
1) Ground it.
2) Ground it with a resistor.
3) Ignore it and leave it floating.
4) Other.
 
I know I should know this at my age, but it's something I've never needed to do before.
 
Thanks in advance.

 
so basically you tie them to the shields, or ground them.

Beagle
so basically you tie them to the shields, or ground them.

I don't know how you'd go about grounding the '-' wire as there is no ground.
This is just a cable adapter (but the shield will connect to ground eventually somewhere).
 
So yes, connect '3' (-) and '1' (shield)
 
From :  http://www.raf-net.com/gallery/tools/Wiring%20diagrams.htm
 

Paul P

Beagle
so basically you tie them to the shields, or ground them.

I don't know how you'd go about grounding the '-' wire as there is no ground.  This is just a cable adapter.
 
So yes, connect '3' (-) and '1' (shield)
 
From :  http://www.raf-net.com/gallery/tools/Wiring%20diagrams.htm
 

The ground is inside each device connected to the shield.  when you connect to the shield, you are grounding.

 
Yes and no
 
You can't ground the '-' within Karyn's adapter.  You can only connect it to the shield.
Either or both devices connected to it will then ground the shield.
 
I know I'm splitting hairs...
 
But this still doesn't take care of going from 2-balanced to 2-unbalanced.
Probably doesn't matter for a headphone connection.
 
 

I bought a $3-$4 adapter/splitter to do the same thing going the other way - splitting a stereo 1/4" output into two separate 1/4" lines from one of my keyboards to feed the audio interface.
 
Super cheap - worked great.  Radio Shack
 
Bob Bone
 

Both Beag's and Paul's schematics are the same and are what I will do.  (The balanced outs are actually in a DB25 connector, but that's not important right now).
 
I should have said Screen, of course.  There's no guarantee that the screen is connected internally to ground though it would be unusual if it were not.
 
Thanks guys.

 
Just for anyone's interest on the subject of balanced to unbalanced connections, the best reference I know of is a document from Jensen Transformers :
 
Doc ID :  Jensen AN-003
INTERCONNECTION OF BALANCED AND UNBALANCED EQUIPMENT by Bill Whitlock
 
This document used to be easily gotten from JT but now you have to create an account to get it.  I just created a dummy account to get through that.  Once you do that, if you just open the above document for some reason it won't contain the schematics, but if you save the pdf doc and then open it locally on your system, the schematics appear.
 

just a quick head's up...
 
connecting the low side (pin 3) to the shield (pin 1) will work most of the time. Exceptions include:

• If the source uses an opamp to drive the low side you can draw excessive current from the source and burn up the opamp.
• If the output uses a cross-coupled topology you can drive the circuit into some nasty distortion when you tie pin 3 to shield.
• If the input circuit suffers from a "pin-1" issue you can reduce the S/N ratio, sometimes significantly, when pin 3 is tied to shield.
• There are also output topologies that will have severe cross-talk when wired pin 3 to shield, but I can't remember what they are, and I doubt you'll run into them in 2015.

The only way to know for certain is to look at the schematic, and sometimes that's more trouble than it is worth. In those cases I start by connecting pin 2 to tip for left, pin 2 to ring for right, and both pin 3s to sleeve. If it is working, and there is no smoke I leave well enough alone. If I have noise problems I then start testing different connections for the shield.
 
These days I use some sort of balancing interface, but that's a tale for another day.

That's why one of my options was to tie pin 3 to shield with a resistor (for current limiting).