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.
• 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 independent mid-boost switch lets you switch the response of the mid-range
A versatile full-range booster
This vacuum tube booster can be used for a mid-boost, treble-boost, and overdrive, in addition to a full-range boost. 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. An independent mid-boost switch lets you switch the response of the mid-range, which is ideal for playing lead. This is a great unit for blues guitarists who wish to highlight their picking nuances.
Newly-developed Hi-Volt technology that overturns expectations for compact effect units
Hi-Volt technology enables the vacuum tube to operate at 200V while still running on a battery. This enables a true tube-driven sound that overturns your expectations for a compact effect unit.
What is Hi-Volt?
VOX has revealed a new vacuum tube circuit technology called Hi-Volt. It delivers high voltage (200V) to a 12AX7 vacuum tube by using 6x AA batteries or the DC9V power supply.
The discrete circuit works at 20V, which is still considered high voltage operation compared to other general effects products. The result is a natural and dynamic tone which is similar to that of a vacuum tube amplifier. Even though vacuum tubes are considered big by modern component size standards, our engineers were able to keep these pedals small, so you don’t have to worry about them taking up too much space on your pedal board.
Gain control that lets you vary the character of your sound
The transistor amplification circuit has also received a good deal of consideration. We've designed the gain control so that adjusting its position does not simply change the amplitude, but will also change the tonal character in a subtle way. From zero to max, it yields an array of highly usable and natural overdrive tones.
Carefully designed power supply circuit that extends vacuum tube lifespan
Since high current flows through a vacuum tube when the power is turned on, we have provided a heater current slow start circuit that extends the lifespan of the vacuum tube and also avoids malfunctions for the AC adaptor.
VOX FL4BT FLAT 4 BOOST Specifications