I use it purely as a boost so I put it at the very end of the chain. I also use it in either 9v or around 12v. I didn't care for it at 18v. It seemed to lose a good bit of warmth and seemed sterile sounding. Just my preference.
I like it before many OD's, but I love it after pretty much any other OD, Distortion, or boost, but before Leslie sims and time-based FX. Wah and phase go in front for me when needed at all.
I will have to fool with it - just trying to get a concensus where to start. FWIW my chain is: Wireless > Wah > Talk Box > Tuner > Compressor > OD > Distortion > Phaser > Chorus.
Then my Delay and Reverb (when needed) goes thru loop...
Depending on your amp and cab, the EP may kind of crush your tone, if placed before gain stuff. Therefore I use it after dirt boxes but before time-based effects such as reverb, delay etc...
It set it at unity and never get it off, except if it's too loud.
Gets sone kind of compression as well. Have to like it. Or not.
I'm resurrecting this thread as a proud EP always-on-er!
I keep my EP booster permanently engaged at the end of my chain with the volume all the way down. The EP works some crazy awesome magic as a pseudo-buffer/EQ. I'm all about it!
FWIW my amp doesn't have an effects loop, so yes- the EP comes after my time-based effects which are all routed through a single bypass loop.
I ran it before ODs when I was using ODs into a clean amp, that way it pushed the OD and got real dirty and compressed when I hit it. Now its my only gain pedal and I run it into a dirty amp.