Mr Black Tiger Boost

[Royboy]

How can I modify this effect so that the first half of the pot is always On and then switch the second half for extra boost. In other words a 2 stage boost

[induction]

This gives 50% boost when off and 50-100% boost when on, depending on the pot setting. You can adjust the resistor and pot values as you like, but it may oscillate when the sum of the resistor plus pot setting exceeds 50k. Use a DPDT if you want to add an led.