Hi. I've built the Mmb-4 about a year ago and I was interested in changing the pots and getting a new pickup like a Seymour Duncan alnico or something. To take off the old pots from the control plate, do I just pull the knobs off and the pots will just fall out? And I assume I can use some Seymour Duncan 250k pots and keep the bass passive ? Thanks for your help.