Erf... I tried to read the manual of the Hantek one to figure out how it's max current/voltage interface works. this is what I found.
Open the power switch, set the voltage, press the VOL voltage adjust selection key, shows the digital voltage regulator tube is selected, the selected digital tube status in the flickering, spinning move ADJUST switch, variable voltage value of the size, again press the VOL voltage adjust selection keys can be selected to change the location of digital tube.
I guess the audiophiles will appreciate that there are not just tubes, but digital tubes!