Simble Predriver

The Simble Predriver strips the Simble concept down to its essence: a preamp boost with no knobs. A single Hot/Cool toggle switch selects between approximately +10dB boost (Hot, on lower notes) and +6dB boost (Cool). Pick attack and guitar volume provide all the dynamic control.

Designed by Lassi Ukkonen, the circuit functions as a preamp, booster, compressor, and upper harmonic enhancer all at once. Input impedance exceeds 2M ohms, meaning it won't load your pickups at all. Output impedance under 50K ohms drives long cables and subsequent pedals easily.

Current draw is just 2.5mA when on (0.1mA when bypassed). Runs on 9V DC with center-negative polarity. Now discontinued. The minimalist design suits players who want Simble-flavored tone enhancement without fiddling with knobs.