The EMG 81 is an active humbucker utilizing a powerful (rail) ceramic magnet. The EMG 81 is usually considered a lead pickup for use in the bridge position. EMG's solderless installation makes swapping your guitar pickups very easy. The EMG 81 was developed in 1979 and released in 1981, hence the model name. The EMG 81 power source can be modified from 9V to 18V by adding a second 9V battery wired in series.
