 As well, since guitar techs need to soundcheck the instruments and amplifiers, they must have a knowledge of the way guitars and amplifiers are supposed to sound in the style of music of the band.This means that the guitar tech must have an ear for music, and for musical tones and sounds.A guitar tech for a heavy metal band must be able to tell whether distortion from a heavily over-driven tube amp is desirable tube clipping or distortion from a blown speaker or damaged power amp.