It's not really that simple.
You could simply wire in a blend pot, but you would have to be sure that the output impedance of both sources feeding the looper are the same, otherwise, the blend pot wouldn't work properly. Unfortunately output impedances are rarely the same. The typical solution would be to add some sort of buffering before the blend pot. It's not really that complicated, but it would require a circuit board (like in the 'split and blend' circuit posted by insomniac). It's not something that would be easy to show in a point to point wiring diagram like your example.
If you can follow a vero layout, then the circuit insomniac posted is a good solution.
Rickenbacker Club #506
Last edited by Projectile : 05-25-2013 at 02:21 AM.