VALCO FX IMP Boost Valco FX

The Variable Input Impedance works best with passive instruments (guitar/bass) and allows tone-sculpting with or without the boost output engaged. Lower settings yield softer dynamics/transients with a notable ‘rounded/vintage’ feel and tone. Higher settings give a sharper high frequency response with a more direct/aggressive transient feel and more perceived gain. This makes for a great ’shaping’ control, where you can tune the pedal for its best response to the pickups you are using and how you want them to react/feel.  Adjust the impedance accordingly to tone sculpt and then use the output to determine how much, if any, of a boost you need.

We recommend placing the VALCO IMP BOOST at the beginning of your signal path (best if you can plug your guitar straight into it) to get the most tone variation/benefit. While it works well later in your chain after other gain pedals (distortion, overdrive, fuzz, etc) to give them a ‘clean’ volume boost, the IMP Boost was designed to work best at the beginning of your chain.

MAIN FEATURES

• Variable Input Impedance Selection

• Output Control ranging from -6dB Cut to +24dB Boost.

CONTROLS

• Impedance Selector– Changes the input impedance value, allowing you to change the tonality of the distortion, dry signal, or any other pedal down the line. Recreates lower impedance sounds of vintage pedals. Allows you to alter/tune the transient/dynamic response of your guitar and signal path.

• OUTPUT – Controls the overall output volume of the pedal.

I/O

•1/4” Input.

•1/4’ Output.

Power: The KGB Dist. JR can be powered by a standard 9V center-negative AC adapter or 9V battery.

Dimensions: 7.09″ length X 4.33″ width X 3.43″ height (180mm X 110mm X 87 mm)

The KGB Loop’s input includes a switch to select between instrument and line input levels, and a rotary selector that provides six possible input impedances ranging from 10 kilohms to 1 Megohm.

The impedance selector can be used to explore tonal possibilities by changing the impedance match to the guitar or bass’s pickups.  The impedance selector is only effective when the input selector is in the “INST” position. When the “LINE” position is selected, the input impedance is 10 kilohms and the signal level is attenuated to be compatible with up to 4 dBu line input levels, suitable for use with keyboards and other line level devices.

The input signal is unity gain buffered by a low-noise audio-grade OPA1692 op amp that feeds the external pedal input through the “LP SEND” jack and the dry input to the crossfader.  The “LP SEND” signal is essentially a buffered dry output.

The phase inversion switch controls a phase inversion circuit at the “LP RTN” input.  This function is especially useful with delay, phase shift and distortion pedals.  The phase inversion switch does not affect the dry signal to the fader and LP SEND jack.

The blend slider implements a sigmoid curve cross fader between the dry signal (as fed to the external pedal) and the (optionally phase inverted) return signal from the external pedal.   The fader is based on a dual channel CMOS variable attenuator.

The blended output is amplified by a second low-noise OPA1692 audio op amp to provide variable post-fader gain of between-12 and +16 dB, controlled by the logarithmic tape “OUTPUT” potentiometer.

The KGB Loop can be powered by a conventional 9V center-negative external supply, or an internal 9V battery, accessible by rotating the quarter turn latch at the bottom front of the pedal and rotating the top panel away from the bottom.