TREBLE: This now comprises one-half of the full EQ stack found in a Vox AC30 amplifier. This knob at maximum boosts the helpful frequencies at around 2KHz and above. At minimum, it flattens out every frequency to -20dB from 2KHz upward.
VOLUME: That trusty knob you know and love.

BASS: This knob at maximum boosts the helpful frequencies at around 100Hz and below. At minimum, there’s a steeper cut at 200Hz (about -24dB) and a huge cut to the sub bass. While not the intended purpose, the Bass control sounds reminiscent of a “depth” knob that some amps have, which is essentially a bass control taken from the power amp section.
GAIN: Rather than control the gain of the amp circuit, this controls the gain of the treble booster in front. The amp circuit’s gain is fixed, allowing to saturate the front end of the amp circuit to your desired level.
The Galileo 4K accepts a 9-18V DC center-negative power supply. The supply must be able to provide over 5mA of current, which is likely all of them. Plugging in the wrong supply (wrong polarity, voltage, AC, etc.) will make your pedal perform poorly, as it will not work (at best) or fry the pedal (at worst). The latter voids your warranty, it’s very very frightening.