the internal presence control should be trim pot(usually blue in colour) I only know the crunchbox has an internal presence control. Not too sure about the tubezone.
okay I emailed them and they replied like almost immediately, haha. its located near the volume control and labelled '203' and is adjusted using a small screwdriver.
no what... it doesnt.. the tone knob.. it determines quite a lot of the bass.. or u can get an eq pedal to tweak the upper end down, and increase the volume..