"Zvex Super Hard On" it is a commercial product.....http://www.zvex.com/vsho.html
Been running the guitar straight into a Boss FV300h volume pedal and notice it has been taking some of the high end out of the guitar so i decided to build one of these little units and mount it on my guitar strap right at the guitar. It has proved an amazing bit of kit, i've never heard such a great tone from my guitars, you can really hear the sound the pickups are shoving out. It will start to break up(overdrive the amp or effects) if you turn the pot up too high, but it acts as a buffer and helps eliminate the capacitance loading effects of the guitar cables and in this case the load effect of the pot in the volume pedal.
Theres a diy layout for anyone who may be interested in building one..its only simple.
http://diy-layout.com/45
Rob
