Dating fender champ
Leo Fender began building guitar amps before he started manufacturing guitars.The first of these amps were the K&F models, which were produced between 19.
The brownface amps originally featured a dark maroon or "oxblood" grillcloth, which was changed to "wheat" in 1962-63.
The twill was first used in 1946 on the Dual Professional a twin 10" 6L6 powered model of which only 400 were made before being renamed "the Super Amp" in 1948.
These early models are commonly referred to as "TV-Fronts" due to the shape of the cabinet when viewed from above.
Make sure it is not pushed too hard into distortion, but set nicely at its sweet spot with just s little power amp breakup (think Little Wing intro).
The overdriven tone with sustain and harmonics can only come from cranked amps and/or pedals.
The Brownface series was introduced in 1959 and discontinued in 1963.