PMT V-TREB, Variable Treble Bleed with PotPrecision Music Technologies V Treb Variable Treble Bleed Bypass Circuit Made in 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