I have the same problem. I bought my Tube Zipper brand new (though I’ve played with it for some time now), and it has never been able to get that “wooo, WOOOOOOOOOooooo” that Peter Stroud does in the demo with the Frequency knob. EHX, are you reading this thread? Do we have defective units, or is it truly the tubes, or what? Pedals are finicky, but this one is advertised to be “WOW, that’s freaky.” Where is my WOW? I want my freaky. I want that “this’ll give you some idea of why it’s called the Tube Zipper” and be able to crank out that jownkoh koh, koh wowkoh koh sound that Stroud did. How do we do it?