Volume: Sets the volume level when the pedal is engaged without BOOST activated.Minimum setting is Unity Gain. At maximum, there is 14 dB of clean boost. Typical settings: For using as a buffer, all the way down (unity gain). For volume boost, around 8:00 or higher.
Boost: Sets the volume level when the pedal is engaged and BOOST is activated (red LED is on).
Tune: This determines the degree of phase shift created by the phase shift filter. Rotate clockwise to sweep from low to high frequencies. Use this knob to find the sweet spot for your solos to cut through. Or use as an EQ to tune your guitar to your or amp, or create special effects.
Color: Sets the amount of coloration added by the phase shift filter. Counter-clockwise mixes it with negative polarity for a filtered sound. Clockwise mixes it with positive polarity for a phased sound. Start at the extreme settings and work your way back to the middle if it's too much. Center setting gives no coloration.
Always ON/BOOST only: Phase shift filter settings TUNE and COLOR are normally applied to BOOST. This switch allows you to apply those settings to VOLUME as well. Configure 2Boost as a two-level EQ, a buffer and a booster, or a buffer with switchable EQ.
Boost Switch: Momentary foot switch toggles BOOST on and off. Indicated with red LED. Switching is silent.
Circuit description
The source signal goes to three places: the two gain stages and the phase shift filter. TUNE controls how much phase shift is applied. The signal appears at the phase shift filter's output in both positive and negative polarities. COLOR controls the filter level by giving maximum positive and negative level at each extreme of the rotation. As it moves to center, the signal drops from the mix. At center setting there is no signal coming from the phase shift filter.
The signal level dialed in by the COLOR control gets mixed with the source signal for the BOOST stage. There is a toggle switch to select whether it gets mixed with the VOLUME stage as well. When it gets mixed with the source signal, the phased or filtered sound is created.
The gain stages, VOLUME and BOOST, are separate and identical. They are not additive or in series. The momentary BOOST footswitch uses silent FET switching to select between them. Status is indicated by a red LED.
The phase shift filter section uses a pair of JRC 3700D Transconductance amplifiers set up as a bank of four all-pass filters. The amount of shift is set by a voltage that iscontrolled by the TUNE knob. A 5-Volt regulator is used to keep TUNE settings consistent whether the pedal is being used at 9VDC, 18VDC or anything in between.
