Determine plus or minus connection for XLR

I'm building pig tails and patch cords for a project  studio.  I'm hooking up mixers that have barrier strips for outputs.  When looking at a scematic of the device which has a 600 ohm output transformer how do you determine which side of the transformer gets hooked to the hot terminal on XLR connection #2 and which side gets hooked to #3?

Does the shield get connected to the center tap or directly to the ground?

The shield goes directly to the chasis, not the audio ground or the center tap.

For the other decision, take a LF sine, say 100Hz, send it through the equipment, record it back directly and throw the equipment and if they both goes the same way it's fine, if they are reversed swap the wires.

JS

The trailerpark method of determining polarity is to mult any signal, don't really matter what it is, as long as it's got plenty of low end, sending one into a mixer channel, the other through the device in question then into another mixer channel, bring up both faders to equal level, and if the sound is all phasey and the bass is  cancelled sounding then you've got it backwards.

This is what I tell people who don't have a function gen and scope, anyways.

The easiest way to check electrical polarity through a chain is to use a diode clipped sine wave.  The flat top clipped by the diode is positive going.  Much more clear than trying to use  random audio.

Gold said:

The easiest way to check electrical polarity through a chain is to use a diode clipped sine wave.  The flat top clipped by the diode is positive going.  Much more clear than trying to use  random audio.

Click to expand...

If you have a scope?
==========
The sum with an parallel path and listen for bass cancellation should work.

If you have a schematic the transformer will often indicate + polarity with a dot.

JR

JohnRoberts said:

If you have a scope?

Click to expand...

Or a DAW.