Hi, I tried to connect a JMP-1 on a JCM-800 2210 amplifier. I'm not sure which send-return input output I need to use. On JMP-1 "Master L or R output" to JCM-800 return ? Or on JMP-1 "return" from JCM 800 to send on JMP-1 - and "send" from JCM-800 " to "Return" on JMP-1. Guitar on JMP-1 input. (with this, all potentiometer control on JCM-800 are non-working) !!! Or ? And were I need to connect the guitar jack ? On JCM-800 "input" or JMP-1 "input" ?? anyway... I'm lost . Anybody can help me please ? Thanks a lot ! Kinds Regards.