Frostwave Funk-a-DuckVerified

From the post

"The Funk-A-Duck is an envelope control filter which can be used to produce a wide range of "synthetic" analog-ish sounds. The input causes a control signal to be generated, which goes up and down as the input signal loudness contour goes up and down. This in turn sweeps the filter frequency back and forth."

• Output Level Sets the output level ;)

• Envelope (Down-None-Up) Controls the amount & polarity of envelope modulation.

• Input Range Sets the input sensitivity, has major effect on intensity of effect as well as overall loudness. Important to set this so that when bypassing, the levels are about the same.

• Res Sets resonance of the filter. Can be turned up to actually resonate, either continually or when triggered by peaks of the input signal. This is one thing that makes the unit rather unique.

• Frequency Sets the filter cutoff frequency. It has a very wide range, so it is possible to have it set so NOTHING at all comes through. Also, when any of the other knobs (input, res, envelope, speed) are adjusted, the resonance freq moves, and needs retweaking.

• Speed Sets attack/decay of the envelope. When fully anticlockwise, the speed is FASTEST. Recommend using in this position, at least until one is familiar with the unit.

• LP Filter / HP Filter Selects the type of filter: lowpass or highpass. Unit will resonate in either mode.

Original FSB thread and schematic are available here.

I've used an LM13700 instead of 2 LM3080.

Drawing it was quite complicated and it came out quite large.

Always double check the schematic before building an unverified layout.

(You may be able to use an LT1054 based voltage doubler but I'm not sure about noise level)

Special thanks go to Digi2t (Dino T.) for drawing this and many other schematics we've been using on this blog.

Here's his video: