Add some funk to your pedal board...and a fixed wah too! The BYOC Envelope Filter & Fixed Wah has 3 parameters when in envelope filter mode: Sensitivity, Range, and Attack. When in fixed wah mode, the manual knob lets you control where you park the frequency, and the range knob lets you control the Q. This circuit uses a 13600 Dual Transconductance Operation Amplifier making it a fantastic sounding envelope filter that's very versitile.
LAZY Sprocket $95
The SG-1 Slow Gear is one of BOSS' rarest vintage pedals and has become very collectible and expensive. It is a Envelope volume swell effect, which means it automatically swells the volume up when it recognizes your pick attack. It is not a reverse delay effect as many people seem to think. This is a fairly easy build. It would be ideal for anyone who likes to use a volume pedal or finds themselves riding their guitar's volume knob with their pinky finger a lot. It's great for getting fake violin attack or faux pedal steel type licks. The BYOC Lazy Sprocket is also a great way to find out why people are going so crazy over the SG-1 without having to drop some serious coin.