The Cooltron Over the Top Boost effects pedal uses a low-voltage 12AU7 tube-type amplifier to deliver the kind of tone that, until now, would have been impossible to achieve in a battery-powered pedal.
OTTB places the top boost channel from a VOX AC30 into an effects pedal. The Treble control can change your tone from sharp attack to a smooth and flowing tone at the second, while the Bass control adds a fuller bottom end at higher settings and a warm, round smoothness at lower settings.