Mini Tube Boost PCB

This tiny little pcb will accept a 5672, 5678, or 6418 subminiature vacuum tube. The circuit yields a clean boost that is quite loud. These subminiature vacuum tubes are highly microphonic and are susceptible to shakes and vibrations, when disturbed with enough force (a typical 3pdt footswitch “click” is enough) it I’ll produce an audible “piiiiiing” sound that will slowly fade. For that reason I suggest using a soft switch circuit of some variety to activate it.