Impedance balanced outs to un-balanced inputs

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Mondy

Well-known member
Joined
Feb 11, 2012
Messages
59
Location
UK
Hi All
I have a cheap Allen & Heath Mixer (Zed10FX) that has impedance balanced main outs (XLR) and AUX outs (TRS) which I need to connect to unbalanced amplifier inputs (1/4" phone sockets). Can anyone tell me exactly how to wire my interconnects? Do I wire XLR out pin 2 to 1/4" tip in, and XLR pin1 out to 1/4" shield in (leaving Pin 3 open)? or do I tie XLR out pin 3 to Pin 1 also or something else entirely?

I thought this would be a simple Google search but I just found myself going round in circles with the myriad of Balanced/Un-balanced issues that seem to exist, so I thought I'd ask the groups wisdom!

Ray
 
In theory, in your case, leaving pin-3 either open or tied to pin-1, would make no difference whatsoever.

Less work as well.
 
Thanks TV!

So for XLR to 1/4" I wire XLR out pin 2 to 1/4" tip in, and XLR pin1 out to 1/4" shield in (leaving Pin 3 open)
and TRS to 1/4", wire Tip to Tip and Shield to Shield (leaving Ring open). Correct?

Ray
 
The biggest problem I have seen with impedance balanced to unbalanced interfaces is when there is disagreement regarding which of the XLR pins is hot... Back in the day some compnaies considered pin 2 hot, and others used pin 3 as hot.

I have seen cases where the impedance balanced leg was grabbed as the output and that no workee...

JR
 
Mondy said:
So for XLR to 1/4" I wire XLR out pin 2 to 1/4" tip in, and XLR pin1 out to 1/4" shield in (leaving Pin 3 open) and TRS to 1/4", wire Tip to Tip and Shield to Shield (leaving Ring open). Correct?
XLR  TRS
1      sleeve
2      tip
3      ring

works well for ALL cases, balanced or unbalanced inputs, whether the input device uses the ring or not.

http://www.uneeda-audio.com/zbal.htm
 
ricardo said:
Mondy said:
So for XLR to 1/4" I wire XLR out pin 2 to 1/4" tip in, and XLR pin1 out to 1/4" shield in (leaving Pin 3 open) and TRS to 1/4", wire Tip to Tip and Shield to Shield (leaving Ring open). Correct?
XLR  TRS
1      sleeve
2      tip
3      ring

works well for ALL cases, balanced or unbalanced inputs, whether the input device uses the ring or not.

http://www.uneeda-audio.com/zbal.htm

That ASSumes the XLR output uses pin 2 "hot", as JR mentioned.

Bri
 
Thanks for your all your help

The mixer is pin 2 hot if the manual is anything to go by. So you say that the best thing to do is wire up an XLR to TRS and use this even if the unbalanced input I need to drive is a mono TS socket? The same for the AUX out, TRS to TRS?

Ray
 
Mondy said:
The mixer is pin 2 hot if the manual is anything to go by. So you say that the best thing to do is wire up an XLR to TRS and use this even if the unbalanced input I need to drive is a mono TS socket? The same for the AUX out, TRS to TRS?
Yes.
 

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