The owner of this amp loves it, but wanted spring reverb, and the ability to dial back the volume. We installed a variable voltage stabilizer circuit, so the amp is adjustable from less than 1/4W all the way to full power.
We also installed a high voltage solid state reverb circuit - as close an approximation of the standard Fender circuit as possible with MOSFETS. The reverb circuit remains at high voltage even with the power stabilizer dialed down, for best reverb tone.