The Fender Champ was noted for the variety of sounds that it could produce,
from clean, undistorted tone at low to mid volume to a harder distorted sound
as the volume is increased. This results from the output tube being over-driven
by higher signal levels at the input.
The characteristics of the output transformer also affect the sound.
To demo the amp, I had a friend play his Gibson SG through
the amp for it's first test drive.
Clean Sound: Low level input, volume around 3.
Distortion: Low level input, volume at 8.