I e-mailed Mesa Engineering awhile back about the loop mod for the 3 Channel DR parallel fx loop to make it serial. I received the same schematic that I now know everyone else gets. I can see the appeal for someone who doesn’t want their signal to be “tainted” by a pair of jfets, but they aren’t amplifying, only opening to allow the signal through. It’s no different than having any other quality part in the path.
More recently, I saw that a company is advertising their bench fee for a different mod and the loop retains some of the functionality afterward. I thought to myself, what would do that? One thing that came to mind while off on one tangent is the idea to pinch the dry channel off. Then the light bulb flashed and blew up over the idea I’m writing. This is not only easier than adding a part or bypassing the jfets, it is entirely reversible. Here’s how to mod the fx loop and gain a killswitch: