Switching off power will not bypass the circuit, you need to try a different bypass method. Switching off power on this circuit will turn off the output so you will get nothing out.
Thank for your answer. I tried without the bypass switch (9v directly in the circuit) and another time I have any sound on the output.
As I have to do this little circuit to have some sound?
1. Does the original circuit work? Just the original circuit from tonepad, no modifications.
2. The second circuit you are showing is a circuit to mix the dry and wet but this circuit is not necessary as the first circuit you show has a wet/dry mix already.
If the original circuit is not working then you need to have tonepad help you to get that working. Once the original circuit is working correctly you can then start to add a bypass circuit.
Is the clip's led always on? Maybe the crystal oscillator is not working, The tonepad design is not containing the capacitor from the FV-1 design note:
"Depending on the supplier of the crystal there can be a startup problem with the crystal,
it is recommended that all designs include a 15pf capacitor between X2 and ground."
I had a similar issue with my pedal, and putting there a capacitor between X2 and ground solved it.