 As well, guitar techs are often expected to set up, repair, and adjust electronic effects, tuners, pre-amplifiers, amplifiers, and pedalboards.To do these tasks, guitar techs must know about a range of audio engineering and electronics concepts—such as impedance, signal phase (for speakers and microphone wiring), and input voltage for pre-amps and effects.To do simple repairs on electronic gear, a guitar tech may have to know how to use a soldering iron and a multitester, and how to do basic electronics troubleshooting.