I've got a Soul Food Bass and a Big Muff Deluxe, both of which give a really loud POP when switched on. I've tried using a battery, different power supplies, different leads, switching on and off a few times and still that pop is there. Do they all do it? From a search on interweb, it seems this happens on the guitar pedals, but couldn't find anything on bass ones.
My whole life seems blighted by electrical pops. If it's not the old Marshall solid state (ditched now, but thanks for the advice, forum people) it's my pedals! Never had a problem with Boss, may go back to them, although the Soul Food is so much nicer.
Cheers,
Bob.