Fender Champ mods part 2 — screen resistor

The Fender Champ has long been a small tube amp favorite. It's a great-sounding five-watt amp that works well not only as a practice amp, but also for recording. Its simple circuit lends itself well to beginning the study of tube amps in general. There have been many versions of this amp over the years and comparing the schematics and studying what changes were made, why, and the effects they had will reveal many principles of tube amp design and function. In this video I discuss the strange lack of a screen grid resistor on the power tube of Champs and its effect. There is a before/after comparison at the end of the video that allows you to hear the amp without and with the screen grid resistor, back to back. Please keep in mind that tube amplifiers harbor lethal voltages inside and that if you do not have experience working with them or are not familiar with the proper safety procedures involved, you should not open your amplifier. The risk of deadly electrical shock is present even when the amplifier is unplugged from the wall outlet and switched off. French subtitles available soon.