The Neutrino takes your guitar playing and creates an automatic wah sound based on your pick attack! The Neutrino V2 is an amazingly small and compact form of the classic opto-coupler auto filter. The opto-coupler based envelope filter pedal was first designed by Mike Beigle in 1972 and is legendary for its funky sound. The circuit has been used by Stevie Wonder, Frank Zappa, The Police, the RHCPs, and of course, Jerry Garcia. Envelope filters or auto-wahs as they are often called, sound particularly good when they are opto-coupler based. The opto-couplers used in the Neutrino have a relatively slow attack and release so they sound really particularly smooth. The Keeley Neutrino gives you three filter settings – low-pass, band-pass, and high-pass filters for tonal exploration into auto-filters. The filters center around what areas of your tone you want to affect. If you want a classic wah pedal sound, try the Band Pass or Low Pass and set the Direction switch for Up! Want that crazy down-sweep sound? Try the High Pass sound and set the Direction switch to Down! Your pick attack controls how much the Neutrino “wahs”. Set how aggressively the Neutrino responds or “quacks” with the Peak setting. With the new V2 Neutrino, you can set the Drive Level which helps trigger the dynamics of the filter, but now you can easily set the output volume with a side mounted Volume Control. No more time spent digging inside to find that wealth of inspiration, and a lot more time getting funky with it!
source: robertkeeley.com