FX loop passive mixer

[greiswig]

Hi, all,

Got a stupid question for you: I recently bought a JFET-based serial effects loop that inserts between the preamp and the phase inverter. The issue that I have with it is the serial part...I *never* run the types of effects I'd put there full wet, and while the circuit is pretty transparent, I can definitely hear a difference.

I'm thinking about making a passive mixer so that part of the signal bypasses the loop. But I'm not sure how to start tinkering with that.

Here's a diagram of what I *think* it might need to look like, with some questions to follow:

(Cheesy text art omitted in lieu of attached jpg)

1. Is R2 even necessary, given that the JFET is probably really high impedance in?

2. How does one go about determining roughly the range of values for the resistors? E.g. for 50% bypass, the total loop resistance should be the same as R1, but what value should R1 be for a tube amp circuit like this?

Thanks in advance for the help!