Question:  

Why does my P2 work on mixer outs but not also on my Mini Stagebox?.  My P2 headphone amp will work connected to a mixer but not when it is connected to a Mini Stagebox.

Answer:

The switch inside P2 MUST be set to Mono. The switch is set in Stereo mode (default), the P2 uses the XLR as a stereo connection.  This is meant to be connected to a stereo TRS ¼" headphone jack.  When in Mono mode, it will use the connection as a balanced XLR.

The only way to use this unit id with a single mono output on a mixer or stagebox.  The Mini Stagebox uses ground compensated outputs.  This ties the negative (pin 3) to ground thru a circuit.  Left is on pin 2 and right on pin 3.  This will not work with the unit in Stereo mode as it shorts signal.

Other devices are fully balanced unlike the headphone amp which is getting a mono signal with +, positive, feeding the left channel and –, negative feeding the right.  This may look like a stereo signal it however is not. It is not good to operate in this mode.

Note- PM1 can NOT be used!

Notice from Behringer-- XLR locking jack accepts an XLR male plug for connection of a stereo personal monitor mix. Signals should be sent from a stereo headphone amplifier to the PM1. Note that the PM1 XLR input is not meant for balanced line signals.