For anyone using one of these Joyo Fuzz boxes, here's a great mod I stumbled across:
http://www.freestompboxes.org/viewtopic.php?f=11&t=14129).
The mod requires no additional components (apparently some capacitors were incorrectly installed at the factory) and takes about 5 minutes, all you need is a soldering iron.
Before I modded the pedal the octave-up feature was completely unusable, now it's actually pretty decent. Enjoy!