Update 2015-03-29: I added a vero layout of the deluxe version. Thanks to Synsound at the tagboardeffects forum for verifying!
Here is a new original design. :)
The Flash Filter Fuzz is a inverter-based squarewave fuzz with a resonant highpass filter and sample & hold modulation. I made layouts for two different versions, a standard and "deluxe" version.
Here is a demo-video of the deluxe version (modulation starts at about 4:00)
I found this pedal kinda hard to demo, but you should get the idea. :)
The controls are as follows:
Intensity: This controls the strenght of the resonant peak. Turn it up and it will oscillate.
Resonance: This controls the frequency of the filter cutoff/peak.
Rate: Controls the speed of the sample and hold modulation.
Bias: This controls the depth and range of the sample and hold modulation. It was originally intended as a internal trimpot, but I found it very useful as an external pot. Ultimatly it should been two different pots to control both range and depth, so the 200K pot is a bit of a compromise, hence the not so perfect sweeping action.
S&H switch: This is a on/off/on switch that has 3 different modes; LFO disengaged, LFO free running and LFO gated by the guitar signal.
With the LFO free running and the intensity turned up into oscillation the circuit turns into a synth/noisemaker thingy. :D
Deluxe version layout and schematic:
Standard version PCB and vero layouts:
This version doesn't have the sample and hold modulation and is alot simpler to build. It's also tuned slightly different so that it doesn't oscillate with the intensity turned up.