FET Guitar Preamp

[BubbaFet]

 

[amptramp]

You can break the circuit into gate resistor, JFET and Source resistor and put this in the guitar or the cable plug.  The rest of the circuit can go in the first box in the pedal chain (although not strictly a stompbox since there is no use for a stompswitch on it).  This allows you to use a pot for the drain resistor to set the operating point.  If you put it on the cable plug, this gives you a 50% chance of making a mistake when connecting, so label it.  If the gate resistor is made variable, you have a tone suckage control.  You could label the gate pot "Talent Suckage" and the drain pot "Talent Boost".  There is no need for a battery in the guitar or cable so you don't need to add a battery access port.