Precision Music Technologies V-Treb – Variable Treble Bleed Bypass Circuit. Made in the USA. The V-Treb Variable Treble Bleed Circuit attaches to the bottom of any volume pot and corrects the problem of high-frequency losses at reduced volumes by allowing the player to control how bright or warm the tone will get as the volume control is reduced. Turning the trim pot clockwise increases the amount of treble bypass for a brighter sound at reduced volumes. Turning the trim pot counterclockwise reduces the amount of treble bypass for a warmer tone at reduced volumes. With the volume at 10, the V-Treb is removed from the circuit and does not affect the sound.