From the build docs:
You might be tempted to call the Pale Horse YATS, but if you take a closer look you’ll see there is a lot more going on. A split-rail supply, tone shifting, impedance and clipping options plus a clever trick (a JFET as a constant current source on the output of the gain stage to increase headroom and dynamics) make for a unique and wide-ranging overdrive that can cover a lot of bases!
From the VFE website:
The PALE HORSE overdrive pedal started as a personal quest to improve the most widely revered overdrive pedal in history. Chasing down the answers led to a unique, new overdrive pedal. The PALE HORSE is so smooth, transparent, and dynamic, you might even find yourself using it instead of your own amp’s distortion. For purists, the tonal constrictions common to mid-boosting overdrives have been removed, taking it beyond mere “green” pastures.
TONE: Active boost/cut of frequencies above the threshold set by the internal FREQ trimpot. Stock setting @ 3.2kHz.
FREQ: Internal trimpot to make the tone control a treble boost/cut, or higher up like a presence boost/cut (stock setting here is about 1/4 up).
DRIVE: Sets the gain in the drive section. From clean boost to a cascading layers of high gain saturation, there’s more than enough range in this control to satisfy any of your tonal needs.
LEVEL: Sets the output level of the Pale Horse…and it can get LOUD!
IMPEDANCE: Sets the input impedance via an internal trimpot. Lower input impedances respond more dynamically to your guitar’s volume knob, and higher impedances will add sparkle to the top end.
COMP: Uses Variable HCC technology to transition between a sweet, asymmetrical drive tone (counterclockwise) to a dynamic mosfet drive (clockwise). In between, there are many shades of compression and tone, with the 12:00 centerdetent position locking in the clean boost mode.
HIGH: This post-gain treble cut lets you smooth out the character of your tone, or crank it up to add some gritty, bright top end.
LOW: The pre-gain bass cut lets you tighten up the bottom end to add punch, or turn it up for a thicker, full-range drive. Makes the Pale Horse a bass-friendly overdrive!