The Guild F40 Valencia guitar has the D-TAR Wave-Length Pickup and Preamp System that combines a thin, piezo under-saddle transducer with an 18v, low-noise, high input impedance preamp, to create a system with twice the dynamic range of typical 9v systems. The 18v preamp is powered by two "AA" batteries and a voltage converter. With 18 volts, the signal has more headroom, so hard strumming won't distort as easily. The acoustic guitar's preamp also has an input for a second source, like a magnetic pickup or a soundboard transducer. Two adjustable trim pots, one for low frequency shelving and one for high frequency shelving, allow you to fine tune and "set and forget" the bass and treble frequencies to optimize the Wave-Length for your instrument's size and shape; enabling you to transparently amplify the natural timbre of your acoustic guitar with minimal coloration. The soundhole mounted Volume and Tone controls give the ultimate in final control over your tonal palette. But pe