Vox TG1FL4BT Tone Garage Flat 4 Boost Tone Garage Flat 4 Boost Guitar Effects Pedal The FLAT 4 BOOST takes advantage of VOX's newly developed Hi-Volt technology and provide not only the warm tone expected from a tube but also the all important feel and dynamics Key Features  Discrete circuitry - the result of a relentless design philosophy  True bypass design provides tonal confidence even when the effect is off  Tough die-cast body that stands up to the rigors of the road  Newly developed Hi-Volt technology allows the tube to operate at 200V, even on battery power  Gain control lets you adjust the tonal character  Heater current's slow start circuit ensures vacuum tube longevity  Full range booster that delivers true vacuum tube sound  An ... Its Baxandall tone circuit allows adjustment from the flat position to the desired boost or cut range Raising the gain will gradually apply a low-cut, giving you an overdrive sound that's strongly reminiscent of sought-after vintage tones