This preamplifier was designed as a stand-alone portable unit, useful to control the signals generated by guitar pick-ups, particularly the contact `bug` types applied to acoustic instruments. Obviously it can be used with any type of instrument and pick-up. It features a -10dB, 0dB and +10dB pre-set input selector to adjust input sensitivity, in order to cope with almost any pick-up type and model. A very long battery life is ensured by the incredibly low current consumption of this circuit, i.e. less than µA.