I just got this Yamaha BB424 used from a co-worker as I've been craving a passive sound (I have an esp/ltd with active emgs). I got it all cleaned up and put some new strings on but now I can't figure out the pickup settings! The pickups are like a fender p bass (Two split at the neck, one rail at the bridge) and there is a toggle switch with three different settings. When the knob closest to the neck is turned all the way down, there is no sound with any of the pickups even with the other knob turned up (makes it a master volume I assume?) The second knob seems to be the volume for the bridge pickup since it brightens the tone. Now this leaves me with the three settings on the switch.. What would they be? At one extreme, it's really dark, the middle setting seems to really increase the output and make it a bit brighter.. the third setting is the brightest of them all and the output seems to be even higher (makes my amp growly/gritty, even though volume seems to drop a tad). Can someone tell me exactly what this switch is doing??