I have a K&K rockabilly system. So after my preamp I would like to use the individual outs and run each pickup thru some effects and combine them back to a mono signal. I have this on a larger pedal board with a mixer. I am trying to keep this board much smaller and not to expensive. I have looked at the Rolls,Nady,Behringer small mixers (volume only) but reliability issues start to run through my head. I just need to combine two signals without loss of tone or gain and without ground loop hum. Does such a simple box exist? Two 1/4 mono female inputs to one 1/4 mono female output? Any suggestions?