Re: Mapex Janus Ergo Double Bass Pedal
Unfortunately I have one of these pedals as well, but I won't get into my negative opinions on it.
Underneath the spring, there is a black knob that adjusts how much pre-load is on the spring. There is a silver knob above that black one that you tighten to ensure that the spring tension doesn't loosen. When you tighten the knob, you gotta make sure you back off the silver knob a little bit so the bolt can move freely, then tighten it back up when you have reached the desired tension.
I'm not the best linguist, but hopefully that helps.