Westone Thunder II active bass wiring diagrams

This wiring diagram is taken from my 1982 (Version 1) Thunder II active bass. It should also be suitable for the version 2 Thunder II active bass, and the Thunder III - as far as I know the only difference between the circuits for these guitars is that the later models have a different pickup in the bridge position.

The volume and passive tone pots are 500K log/audio, the active tone pot is 500K with a centre detent. The tone capacitor is 0.022 microfarad Mylar.

The active on/off and phase switches are DPDT mini toggle switches, the dual tone switch is a 4 pole changeover mini toggle.

  1. This battery negative lead connects to the switched earth terminal on the jack socket, the power supply circuit is completed when a jack is inserted.
  2. These two wires are soldered to the backplates of the pickups

The original switches have an earth wire soldered to the metal parts of the switch body - this is not necessary and if you are replacing the switches with modern ones (Which usually have plastic bodies) is not advisable - connect the earth wire directly to the back of the active tone pot and not to the switch bodies as shown below: