Peavey XR684 caution

[g1]

Not sure if Peavey does this in other models, some of you may have dealt with it before.
Peavey flips the wiring on one of the (two) amp outputs. That is, the tip is grounded and the sleeve carries the output. This is I guess so they can more easily have another output jack that is for 'bridged' operation.
I couldn't see any output on the amp2 out until I connected my scope to the sleeve by accident. There it was. Fortunately I did not connect my scope ground to the sleeve or I would have at very least found out how good the protection was.
After this discovery I looked much closer at the schematic and saw the note about the jumpers at the amp2 jacks.

[J M Fahey]

Weird.

Nothing to be gained in these single power amp models.
orYes, it may be useful in dual power amp ones which can be used in dual mono, stereo, *or* bridged modes, but in any case I would provide an extra inverting switch, properly labelled with all the options.

As done, they "should" provide a written warning, not only on schematic or user manual, which can be lost, but on back panel itself.

Oh well.

[glebert]

I was trying to figure out how this wouldn't cause phasing issues when in stereo mode for any content that was common to left and right, but looking at the full schematic the models that have bridge mode add an extra unity gain buffer (U202) in the PA2 path to invert the signal.

[x-pro]

This is to reverse the phase of the signal.