Oh that's not funny (yes it is)

Anyway @Flipmuc is from Germany and he struggles with English. Welcome to the Fender Rumble Club @Flipmuc. It is a shame you are experiencing trouble.
Try this: With nothing plugged in, no bass and not even a speaker cabinet. Plug in your headphones only. Put all your controls at 12 o'clock (high noon), yes even your gain and master volume along with all EQ controls. All voicings OFF. Overdrive OFF. Do you hear hiss in your headphones? If yes, how much? A little would be normal operational noise. A lot would mean your amp needs repair. Lets start there.