How Amps Work - Rob Robinette Power Supply. Now that we've covered the signal flow I'll go back and cover the other amplifier components that I didn't mention. Wall plug power of 120 volts AC (USA or 100, 220 or 240 volts AC in other countries) runs to the fuse F1er guitar amp fuses are MDL type "slow blow" or "time delay", size 3AG, 1/4 inch (6mm) wide by 1 1/4 inch (30mm) long. Fender Guitars | Electric, Acoustic & Bass Guitars, Amps, Pro Audio Since 1946, Fender's iconic Stratocasters, Telecasters and Precision & Jazz bass guitars have transformed nearly every music genre.