using aux send/return... mono and stereo question

Gear in question:
1- Mackie Onyx 1220i
1- MicroKorg synth
1- MPC 500
1- RE-20 Space Echo pedal

I want to have the Space Echo pedal setup so that I can apply so much of a return delay effect on my MicroKorg channel (50%) and so much return effect to my MPC 500 channel (10%).

The manual says the Aux Sends are MONO and have STEREO Returns. Now my question is... if I have a stereo sample playing on my MPC 500 (some stuff in the sample plays through the left speaker only and some stuff plays only through the right speaker)..... does it mean that the MPC signal will be combined in MONO, out to the Space Echo pedal?

What's the point to sum it to mono, wouldn't the return signal just be a mono signal with a stereo delay from the Space Echo?

How would I get a Stereo signal OUT TO the Space Echo and then a Stereo Return BACK into the mixer?

AmpleSoul wrote:.. if I have a stereo sample playing on my MPC 500..... does it mean that the MPC signal will be combined in MONO, out to the Space Echo pedal?

depends on how the mixer is set up, and how you have your gear plugged into the mixer (two channels, one panned left, the other right?). but yer not going to get stereo out through a mono connection.

AmpleSoul wrote:What's the point to sum it to mono, wouldn't the return signal just be a mono signal with a stereo delay from the Space Echo?

correct. the fx might be stereo even though the source through the fx is mono.

AmpleSoul wrote:How would I get a Stereo signal OUT TO the Space Echo and then a Stereo Return BACK into the mixer?

if the mixer only has one aux send, then you've got that limitation. if the mixer has 2 sends, you could use one for each channel, that would work...but if one of your sources is mono and the other is stereo, then you got to be careful to send the mono source to both.
otherwise you might could hack it with creative mixer routing, but that would take knowing the mixer and its capabilities better than i do.
edit: i just looked at that mixer and yes it has 2 sends, so you could use one for the left channel and the other for the right. this won't work on the stereo channels, as i guess it probably does sum the stereo signal to mono for the sends. you need to do all this manually with the mono channels and get your pans right.

i also would say, just keep in mind that you don't HAVE to use the returns...i usually run my fx back in through another channel just so i have more control later.
also, consider if you really need that sample stereo - i find most times they end up working better mono.