I have a friend's American Jazz bass in for repair, the neck pickup is not working. That got me curious about the S1 switch, so I looked it up to see what it does. My question is, how valuable is the S1 switch, is having the option of having both pickups in series useful? I have a Fender MIJ Geddy Lee Jazz and I could easily add a push pull pot to the tone pot, to get the functionality of the S1 switch. I may have to do this to my friend's bass if he wants that feature and it ends up being the switch/pot that is the issue.