We have offered the Q2 barebone version (without a knob) and the Q2 barebone knob version (with an added knob on the board) for customers' choice. So you can directly head for the Q2 barebone knob version if you want a knob.
Manually installing a knob on the PCB requires extensive soldering experience and this process may affect your warranty. We do not recommend this and do not sell the rotary knob separately.