thanks uncle Dave,each keyboard has two cables connected to the RIGHT and LEFT/MONO jack of the mixer.U mentioned take the effect send and plug into deltafex input(which input,right or left/mono?)and take the deltafex OUTPUT and plug into effects return(but which one is the effects return??)Both jacks of the stereo channel had been occupied by cables from kb.
Do I use only stereo channels(R & L/MONO)and not mono channels(LINE IN and INSERT)?


please 4give me for stupidness.