K&K Pure XLR PreampThe Pure XLR Preamp features + 20 db bass, mid, and treble controls, plus an adjustable input gain control. Its noiseless circuitry provides unsurpassed clarity and power and the adjustable input gain allows you to dial in the precise amplification factor needed for your instrument. The addition of the phase switch is one of the most important tools for live sound amplification of any acoustic instrument. Phase switches are usually marketed as a