H. TREBLE - Adjusts the level of high frequencies of your Vibro-King. NOTE: Like many vintage amplifiers, all tone controls are pre-distortion and adjusting them determines how the amplifier will overdrive. I. BASS - Adjusts the level of low frequencies of your Vibro-King. Performance Tip: When overdriven, the tube power amp enhances bass frequencies. It may be necessary to use lower bass settings when playing at high volume settings. J. MID - Adjusts the level of the mid-frequencies of your Vibro-King.
K. SPEED - Adjusts the speed of the Vibro-King�s Vibrato feature. Turning this knob clockwise increases the speed of Vibrato oscillation. L. INTENSITY - Adjusts the level of signal modulation of the Vibro-King�s Vibrato feature. Turning this knob completely counter-clockwise turns the Vibrato feature off. The Vibrato feature can also be turned off via the footswitch. M. PILOT JEWEL - Illuminates when the Vibro-King is receiving power. Should this bulb burn out, turn off and unplug the amplifier, unscrew the pilot jewel and replace the lamp with a type T47 bulb.