With vocal or guitar pedals, Is there a difference between one side of a stereo signal (with no panning) vs. a mono signal?

Question

I wanted to try to get two mono XLR signals out of my TC Helicon "Play Electric" Vocal Processor, (which only has the option of ONE mono signal, or TWO stereo signals) so this led to a question which is not explained in the owners manual.

After doing a little research I think the answer may lie in whether the "stereo" signal is just "stereo" or "true stereo" and which of these exists in the outputs of guitar pedals, or in this case a XLR vocal mic pedal.

So here's my question: Is there any difference between 1 side of a "stereo signal" (compared to a mono signal), if you do not run the L+R stereo signals into a mixer and "PAN" them to either side?  In other words (I was hoping to have 2 mono signals, but instead) if I take the 2 STEREO XLR signals that ARE available (for my Mic outputs) on the back of my Play Electric pedal, and if I do NOT use a mixer to pan them in any way.  Then is there any audible difference between each side of those 2 L+R "stereo" signals, and an actual "Mono" signal? 

Answer 1

As I read it, the question is, is the L or R signal of a stereo source the same as a mono signal.

No. If they were the same, you'd have double-mono. But carry on reading anyway.

The TC Helicon "Play Electric" Vocal Processor has Left and Right Stereo outputs at the back. Often, devices which output in stereo (e.g Keyboards, or some guitar pedals) also supply a mono output if only one of the connectors is plugged in. That doesn't seem to be the case with the Helicon, but you shouldn't see a problem unless you're using an effect that needs stereo output (e.g a Ping-pong delay). For a looper, you won't have an issue - just use one output cable, and you'll be fine. There will be a difference between L and R, but it'll be so minor, you can ignore it.

In live performance, it's actually pretty rare to see a stereo feed - we have enough issues with speaker delay times in a big room, so we don't want to worry about left and right as well.

To clear up the confusion of stereo and panning; Stereo will be the signal from the performer, generally a keyboard player. We can either convert that to mono (they'll never notice :p ), or we can let their left signal go left, and their right signal go right. If a performer sends us a mono signal (much more common) - e.g a guitarist - we'll pan their signal to the left or right of the stage, usually to match where they're physically standing on stage. Doing that gives some perception of width in the sound stage.