The FatPants design began as an alternative to the “pedalized” versions of the input stage of the Echoplex that became popularized a few years ago. Over the course of the two previous versions the design has evolved, and the 2012 version is no exception. The 2012 version adds a JFET input buffer, a new Body switch for high-gain/full spectrum boost and a re-tooled output section. These changes add versatility and dimensionality to the previous design. The FatPants 2012 is capable of a wide range of boost and overdrive and will serve as a perfect compliment to push your tone into saturation while retaining note clarity and dynamics.
Fat – Sets the overall gain of the boost.
Lvl – The output volume.
Body – Selects between a mid-range and full range boost. In full range mode, it also adds additional gain.
You may encounter some scratchiness with the Fat control when the Body switch is off. This is normal. Unfortunately, this cannot be eliminated from the design without altering the overall character of the effect. The Fat control works in concert with the 22n cap to produce frequency-dependent gain. As the control is turned up, it applies increasing gain to the upward filter. This results in increased pick attack and dynamics. When the control is down, the filter is also lowered, but since the overall gain is lowered at the same time it does not “muddy up” the signal.
Setting up the FatPants:
Leave the Body switch off, set the Fat control to max. Adjust T1 until you read approximately 9v on the drain of Q2 with your multimeter. Tweak as desired for maximum gain.