tiny giant amp help!

[jogina111]

Ive built a tiny giant amp by music-pcb.com and its built good and I like the cleanliness. I added a fetzer valve but theres  sound leakage present  when the tg pot is 0 and the fetzer valve volume pot at max is this normal?I think of removing the fetzer and add a another preamp that could go to a good overdrive and maybe with a tonestack or volume control.
Any suggestions on what good preamp to add and exactly how to wire it on the tg,  because it hums more with the fetzer valve on and maybe its a wiring problem, Im not quite sure.. Please help