The lowest gain setting gives you get a quite unaltered clean sound,
turning up the drive control then introduces harmonics and slight compression
and natural breakup when you hit the strings harder, just like the real thing.
Turn it up more and you get all the growl and punch of a cranked non-master amp,
fully in control of your picking dynamics and guitar volume.
Even with the drive all the way open you can go back to a clean rhythm sound
just by rolling off your guitar volume.
The passive tone controls are not there to bend the sound but to dial in
the perfect tone with your gear. Even at extreme settings, the Krunch King
never sounds artificial, harsh or fizzy.
Operation should be pretty straightforward, but just in case you can
download the manual here.