Have anyone used Craig Anderton's Envelope Follower with good results?

[gigimarga]

Hello,

One of my dreams is to make an analog stompboxes which to work like Boss Dynadrive (an overdrive/distortion with the amount of distortion controlled by the strongness of the picking).

After i made some tries without optocoupleurs, i finished by buying a CLM6000 and making Anderton's  Envelope Follower.
I used it to control a MXR Distortion+ clone (boosted by a MOSFET Booster).

But the result disappointed me very much: it respond too slow at the dynamic of my picking, the decay of the notes becomes poor (gated), it's very hard to set the pots, etc.
As i've read in the text I replaced the 39uF cap with a 33uF one and the 1N4001 with a Ge diode, but the imporvements were too "light".

So, my question is: "It's possible to make what i want in an analog way or better i must to buy a Dynadrive (i know that's digital, but i like it)?"

Thx a lot all!

[earthtonesaudio]

Sounds like you want faster attack/decay on the envelope follower part.  There are some tricks that can help...
But first check out Mark Hammer's article "The Technology of Auto-Wahs/Envelope Filters" over at hammer.ampage.org (I think it's also available on GEOFEX).  Lots of good pointers there.

So if you want faster decay, that's simple, put a resistor (or pot) of a large-ish value (between 220k and 1M) in parallel with the big cap at the end of the envelope section (the one that charges up).  This will let you discharge the cap more rapidly (and more completely) than it would through the LED.

If you want a faster attack, that's a little more tricky.  You normally would reduce the value of the resistor that leads into the charging cap, but you can only reduce it so much before you start to hear audible ripple coming through.  But there are some mods you can do that will let you have a much faster attack. 
First, C. Anderton's envelope follower is a half-wave rectifier if I remember right.  You can cut ripple in half by switching to a full-wave rectifier section, and in half again by capacitively coupling to a second full-wave rectifier section.  This will (in theory) allow an attack time 4x as fast, which should be good enough.

Good luck!

[Mark Hammer]

If you want VERY fast response, then perhaps you want to use a Photo-FET optoisolator like the H11F1 or H11F3.  The response time on these is fast enough that if you are looking to use them for somewhat longer envelopes, like for auto-wahs, they can introduce too much envelope ripple (actually they preserve the envelope ripple already there, rather than blurring it like slower LDRs do).  However, if you are applying them to events that come and go in 200msec or less, then you won't really notice the ripple as much.