This is how I understand it. (Please keep in mind that for me, two brains would only increase the amount of conversations of the people inside my head):
The trim pot on the 3-way is a gain boost. It allows adjustments of how much gain you want to add to the pickup.
It?s an off/on/boost. The off position is for just that, to turn the pup off. I guess you could achieve the same effect by turning the gain pot down, but it does come in handy when wanting to introduce a predetermined, specific volume to into the mix quickly.
Mica has made it clear to me in a previous post (I think it was the one about the square blue plastic thingie?.) that this is not a Q switch.
Great picture Tom.
