Why do the g-b-e non-wound strings have higher output than the wound e-a-d strings?
Most likely the player is using some type of non-ferrous wrapped string on the e-a-d and the plain g-b-e may be of a larger diameter spring steel. The non-ferrous strings have a much lower attraction to the magnetic field within the pickup and generate less output. Other factors that cause less output can be the balance of the pickup, pole adjustment within the pickup, balance and configuration of the coils and magnetic calibration of each pole piece.
