Very Bizarre Filter Revisited

A while ago I came up with a design for a very bizarre filter which attempted combine a fuzz distortion with resonant low pass filter.  Unfortunately the prototype did not pan out.  This is a second attempt at a bizarre filter.  The idea is not to create a certain type of filter but to deliberately introduce distortion into a filter. 

This design is based on the new filter Ray Wilson is using on his Noise Toaster.  The Noise Toaster is an excellent sounding box which gives you a lot of options in a small space.  I was looking for a simple filter design so that I could try out some experiments without using a whole pile of chips.  The advantage of this filter is that it uses only one op amp.  I had been experimenting with Ray's Weird Sound Generator filter since it is very simple.  This new filter is an improvement over the WSG filter.

The first modification I decided to try was putting in some diodes.  I found that putting a diode and a potentiometer that could be switched on and off in the resonance section allowed for a lopsided resonance which should give some unique character to the sound.

The second modification I wanted to do was to subtract a low pass signal from the resonant low pass signal. That should result in just the resonance from the signal.  Next I wanted to add some hard edges to the signal so I passed it through the an op amp at high gain.  Finally I added another resonant filter at the end to reintroduce resonance on the newly created peaks.  Leaving in all of the controls gives nine different controls for messing with resonance and distortion.

The left trace shows Ray's original filter, the next trace shows the diode modified filter, the next trace shows the clipped resonance signal and the next image shows the re-filtered signal.

I have not built this device yet, I will have to wait to see if it works out.  If I build it I will post a video.  I am hoping to add a filter to a NAND synth so I may use this one.

Heavily Modified APC

This is a heavily modified Atari Punk Console.  Modifications include pitch and mod Cv inputs, resonant low pass filter from the Ray Wilson's Weird Sound Generator, dual low frequency oscillator with cross feedback, selector knob for up to six different capacitor pairs ranging from control frequencies to high pitched oscillator frequencies.

 The circuit for this is on the bottom right:

Analog Sequencer

I finished an analog 10 step sequencer based on one of Ray Wilson's designs with some modifications.  For one thing I made it based on 9V so I could use my standard power supply.  I used a 555 for the clock instead of Ray's clock.  I ended up leaving most of the gate generating part which I later regretted but I would need to add a daughter board to fix it.  I used ten different colored LEDs on this device.  The 10 knobs control the voltage sent to the left output.  The knob by the left output controls glide, the knob by the right output controls step time.  The right output is supposed to be a gate but it only works if you have every other switch up and down.

Another issue is that it outputs a voltage from 4.5 - 9 V rather than 0 - 9V or -4.5 - + 4.5 etc which is problematic with most other synths.  In the next revision I would try to change that as well as a few other things.

Anyway, not too bad for a first prototype.  The videos demonstrate how it sounds:

And another:

Accompanied by a Yamaha CS01 analog synthesizer using a breath control to modulate filter cut off and processing both through a Lexicon Vortex.  The sequencer is modulating  a modified Atari Punk Console that is part of the Thing 2 device.  That device also has a NAND synth, noise generator and starve features.

I added a resonance knob to the CS01 as can be seen in the video.

Here are some pictures of the sequencer in progress.