Envelope detector for phaser like Polyphase or Pigtronix EP-2?

Started by Mr. Lime, August 26, 2019, 12:55:17 PM

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Mr. Lime

Thinking about the EH Polyphase which is quite a complicated circuit I wondered if there's a chance to simplify the core of the envelope detector.

While the Polyphase has basically two independent LFOs, one of them has the envelope voltage added to the modulation that drives the LEDs.
The other LFO can be swichted instead but isn't really necessary imo.

I would rather have a Mutron kind of phaser (Deadendfx Calypso) with a simple half rectifier envelope detector and the option to turn the depth of the LFO down to zero so the phaser acts as an envelope all-pass filter.
The EP-2 takes use of phase inverting the envelope which delivers a funny effect.

Now my question; what envelope detector would you implement and how?

Do we run danger in killing the LED with too much voltage added and how would someone limit this?

Looking at different designs I found the MXR envelope filter with a CD4049 or a Lovetone Meatball kind of detector from David Rolo:



What do you guys think would be simple enough for a little daughterboard?
Thanks for help