Hi Alf
You certainly can, here what I do :-
1. From menu, select Mike settings and turn off noise gate.
The pitch settings I need to look into how these affect the sound, leave as default for now.
2. Guitar plugged into mike socket:-
Select Mixer Panel from menu or assignable button
Go to panel 2 on mixer panel and select effect.
Go to Assign part setting RHS of screen
Go to insertion effect 20 on screen 3 (the only effect available for mic setting) and set to mic
Close screen and back to mixer screen.
There will be an effect selected which can be changed if you press the existing effect on the touch screen.
Away you go.
Cheers Terry