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Vintage threads from the first ten years

Envelope - help

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8/20/2000 4:24 AM
Leonardo	Envelope - help Are the Electro-harmonix: Zipper , and Dr. Q (also Dr. Quack) envelope filters??? Wich one do you recommend?? What do you think of the Mutron III too??

8/20/2000 5:36 AM

Leonardo,

I built both the Dr.Q and Dr.Quack auto-wah filters. I had a hard time trying to adjust the trimmer pot in the Dr.Q circuit to get it to work correctly, scrapped it for parts for the Dr.Quack. Dr. Quack is a much better circuit with the additional components to aid the input signal and getting the op amp to funtion properly. It would be a much better choice of the two in my opinion.

As for the Zipper and Mutron I do not have any experience with those circuits. Anyone else try them?

8/20/2000 7:48 AM
Ryan L.	I highly recommend R.G. Keens Mutron III clone the neutron. When time permits I'm gonna build a Dr. Quack but for the few extra bucks the Neutron is killer, no headaches and you're quacking in about an hour!

8/22/2000 12:40 AM
Leonardo	Could you please send me, or let me know where I can get The Neutron schematic??? I've looked for it everywhere, but still did not find..

8/21/2000 2:51 AM
Leonardo	Is the Dr. Quack an auto-wah or an envelope filter ??

8/21/2000 3:26 AM

It is both. An auto-filter/auto-wah IS an envelope-controlled filter. ECF is a term derived from the early days of analog synthesizers. Auto-filter/auto-wah is a term derived from the perspective of guitarists.

The Dr Q/Quack is an envelope controlled bandpass filter, which can get thin-sounding, because it loses bass when it sweeps. The Mutron incorporates a state-variable filter, which the user can tap high-pass (everything above a certain frequency), lowpass (everything below a certain frequency), and bandpass (everything near a certain frequency) filter sounds from. Some other commercial products (e.g., Ibanez Auto-Filter) work the same way. Although bandpass filters seem to be easiest to design (one often only needs to vary a single control element to tune the filter, in contrast to other filter types), many people prefer lowpass filters because they retain the beefy parts of the note. The Moogerfooger Lowpass Filter is an excellent example of this.

I'm working on a technical paper that I hope will explain all mysteries about ECF's. It's coming along nicely, but unfortunately I have to go in for some medical stuff in a little over a week and expect to be laid up for some time, so it's a real horserace to see if I can finish it before then. Maybe I'll just post what I have with an apology and a "come back for the rest" sign.

8/21/2000 4:15 AM

quote:
"'m working on a technical paper that I hope will explain all mysteries about ECF's. It's coming along nicely, but unfortunately I have to go in for some medical stuff in a little over a week and expect to be laid up for some time, so it's a real horserace to see if I can finish it before then. Maybe I'll just post what I have with an apology and a "come back for the rest" sign.
"

Hope it's not serious, (ummm...the medical stuff) Mark.
I also hope it's at least as good as the "Secret Life of EQ's" heheheh. We need some long articles in your inimitable style. But no damn rush --get well first,
-Eric

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