The CTP-3 CoolTube, the first onboard tube preamp for acoustic guitar, produces a rich, full sound. It takes its name from innovative Takamine technology that runs its 12AU7 dual-triode vacuum tube at very low voltages-so low that it stays cool to the touch-with variable tube tone that can be adjusted from bright and brilliant to thick and warm. The full-range EQ section uses shelving filters to sculpt bass and treble frequencies, with semi-parametric shaping control over the midrange. A control knob adjusts the frequency from 250Hz to 5kHz, and a pinpoint-precise onboard chromatic tuner is standard equipment. Other features include Mid and High cut switches for a second pickup.