I’ve got a 2010 American Deluxe Jazz Bass. This bass’ active preamp has a “passive” tone knob. It’s a nice feature for when you want some control in passive mode.
However, I wanted a the knob to work in both active and passive modes. After reviewing the circuit, I found that it’s a really simply mod.
Note that this mod should work with any “Deluxe” bass that has the active/passive switch. Older models do not have this.