You can put a RC Network (resistor & capacitor) between your #2 and #3 lug of your volume potentiometer. The #1 lug is grounded. Fender used a .001 mfd capacitor. I like using a passive control and it’s quite simple to do. I like using a 150k resistor in parallel with the .001 mfd capacitor. It gives the pickup better fidelity as you roll it back to zero. Make sure you are using 250k potentiometer for your volume controls with Fender style single coil pickups. Pots should be from 300k to 500k audio taper on instruments using humbuckers.

The best thing about passive controls, it allows you to do lots of experimenting without harming the instrument. You can easily take out what you put in. Several times when I was recording in the studio I would plug my guitar into a capacitor subsitution box. The positive end of the guitar cord would be in series with the capacitor subsitution box and out to the amplifier. You can change the tonality of the pickup you are using. Try hooking a bass up to it too. When using a .0047 mfd capacitor in series you have a similar sound to Chris Squire on the early Yes albums. If you can’t find the capacitor subsitution box, try making your own.

Use low voltage disc capacitors. Here are some to try. (mfd.) 25-50 volts

.01 .022 .033 .047 .068 .001 .0022 .0033 .0047