Tibetan Quaalude - Sunn Model T style preamp/ distortion
Tibetan Quaalude is my recreation of the fabled Sunn Model T amplifier sound in a preamp pedal format. Circuit is executed with carefully selected JFET transistors and a few cascaded gain stages (just like in a real amp), what allows to reach vast amount of available tones with that recognisable, fat growl. Pedal includes additional high gain JFET boost section in front of the preamp, which greatly extends gain range and sounds excellent as a standalone device.
Tibetan Quaalude can be used as a typical overdrive/distortion pedal, clean preamp, booster or other pedals 'platform', while it's serious output volume also allows to stack it straight into external power amplifier - thanks to the high gain output stage providing additional volume capacity and tone shaping, for even more real Model T resemblance. With inclusion of output stage it's possible to use traditional FMV 3-band tone stack not only post-distortion but also pre-distortion, what extends tonal range even further.
CONTROLS:
See block diagram document representing internal stages sequence to better understand pedal operation. Each stage of pedal's circuit provides different harmonic content, so distorting any of them yields in a different overall sound.
- boost sets dirty booster output level
- normal/brite knobs set channels output level
- bass/midrange/treble - interactive EQ
- volume sets total preamp output level (in front of output stage), the same operation as 'master volume' knob in Model T amplifier
- master - true master volume control (at the very end of TQ circuitry).
Be careful with tweaking volume and master knobs - pedal can get deafening loud.
INTERNAL CONTROLS:
- high gain boost switch - down position for moderately dirty boost, up position for very dirty boost
- ultra lo switch - down position for original Model T voicing (lowest bass range is attenuated), up position for boosted lows (lowest bass range is flat)
- boost mode selector - separate mode for standalone use, slave mode for 'channel' operation activated when 'standby' footswitch is on
No battery operation possible with this pedal. Feed it only with a 9V DC negative center isolated power supply.
