Voodoo Lab

Uggh does it have to be so hard??!!
Equipment-Mesa RoadKing v1 - GCX - Groundcontrol - MXR EVH Flanger -MXR EVH Phaser - MXR ZW Chorus - Boss Chorus 2. Cables are EA Monorails

Problem-Running these pedals thru the effects loop 2 on RK. When i engage either chorus, I have just a little volume drop. But if i choose either EVH pedals, Bam volume drop by atleast 70%. Now why im posting in VL's forum. Is that even with the pedals turned off but still connected to the GCX, If i choose either of those 2 i still have the volume drop with the pedals physically off. If i unplug the pedals from the GCX than choose those channels, No vloume drop but of course no effects. Dunlop says its a VL problem. I dont agree but dont have any where else to look for help. Ive have thrown money at this like an insane man but still this... Really?? Im pretty sure the pros dont run a straight signal thru the front of their amps.
Any ideas or forward searches?

Do you get a volume drop if you connect any of these pedals directly to the effects loop of the amp?

Yeah it does, but not as bad. I know where ya going. At this point im thinking its an impendence problem, I guess.