Envelope Follower adjusting FX/Clean Mix

[KarenColumbo]

Hi there,

This is something that's been going round my brain for ages. I'd like to control the direct/fx ratio per input "velocity" just like an autowah does with the center frequency of the filter.

Since I'm very eager but not really an expert: Could some kind soul here point me in following direction?

1. Is there some schematic of an envelope follower only? I mean just the follower circuit?

I gather I could use an optocoupler to "simulate" the fx/direct mix pot in the following fx circuit, e.g. a phaser

Does that maker sense at all?

thx in advance - very much appreciated!!

[Kipper4]

Hi Karen and welcome aboard.
I think I kinda get what you mean but perhaps you could expand a little, maybe you've seen/heard the kind of effect you're after before.
There are many ways to use an envelope follower.
Using it to alter the depth of said effect is one.
There are many variations of envelope followers too, full wave rectifier, half wave.....
How far on are you ?
Have you previously built some effects?

If you just want us to point you at an envelope follower schematic then please feel free to ignore the above and go look at GeoFx technology of auto wash here

http://www.geofex.com/article_folders/ecftech/ecftech.htm

Again welcome to the mad house

[Mark Hammer]

What is described is essentially this pedal: http://www.effectsdatabase.com/model/toadworks/pro/enveloope#
Not sure if Toadworks still makes them.

[rutabaga bob]

Welcome to the forum, Karen!  You'll like it here!
Larry

[EBK]

What is described is essentially this pedal: http://www.effectsdatabase.com/model/toadworks/pro/enveloope#
Not sure if Toadworks still makes them.

Not sure Toadworks still exists.  I've been trying hard to get a schematic of that.  Give me a bit of time, and I'll post some of the closest things I've found...


1.  http://moosapotamus.net/files/stompboxology-envelope-effects.pdf.  I remember one of these looking good...

2. THIS! An Enveloope work-alike design
http://www.diystompboxes.com/smfforum/index.php?topic=67443.msg538459#msg538459

3.  This one helped me to think about different techniques on this theme
http://www.diystompboxes.com/smfforum/index.php?topic=112383.msg1037042#msg1037042

[Kipper4]

Neat Mark.
I could get into a project like that....


Yay I'm all ears (eyes) Eric

[KarenColumbo]

Just returned home and being overwhelmed by the fast and friendly responses <3

Will read them, think about my post and specifying more and respond tomorrow, since I'm knackered after a problematic gig.

THX people!

[Mark Hammer]

Not sure Toadworks still exists.  I've been trying hard to get a schematic of that.  Give me a bit of time, and I'll post some of the closest things I've found...

A quick search indicates that Toadworks does not exist anymore, but the owners have rebranded as TEN Effects.  They appear to have pretty much dropped most of their earlier products, including the Enveloope, prefrring to focus on the Howard Leese Flanger.

Perhaps someone might write to them and ask nicely for some tech info on the Enveloope.

[Kipper4]

It's freaking 2.30am I just got home after 12hrs travelling. With no internet. Imagine that.
I know wild ain't it.....
Only to find Eric has dotted the I's and crossed some T's.
I just scanned some of those articles.
My poor brains about to explode.
I can't wait to see how this pans out.
I'm gonna be breadboarding some stuff and trying to digest some of the concepts.
Fanks

Tic tic boom.

[KarenColumbo]

As to initial questions: I built about 10 boxes in the course of the years. I'd say 50% of them actually worked, one or the other were even researched and developed by my humble self. The rest just sat there and did nothing. I have no training in electronics, be it formal or self-taught. it seems there's a barrier in my brain that don't let through any actual facts. So I don't even know what a capacitor or a transistor actually does, even though there's some 50 centimeters of relating literature sitting right in front of me. It just escapes me.

But it's habit forming - the schematic hunting, the hand routing, the pcb etching, the drilling and the wondering what went wring (or right). The why is something I will eventually internalize, if need be I will take on a course or something if I'm not too old by then.

My first thing about this envelope follower theme was a successfully built autowah (a schematic from "Elektor" magazine which sadly disappeared from my drive in the last 5 years).

The goal would be a "velocity sensitive chorus pedal". And the chorus effect should affect only the (adjustable) frequency mid and high range, which, I gather, is accomplished by splitting, filtering and finally mixing the signal paths. I tend to have a look at Rod Elliotts excellent website (http://sound.whsites.net/index2.html), especially his "Designing with Opamps"-articles (http://sound.whsites.net/dwopa.htm).

I had a good deep read of the links you kindly provided, especially, if by far not solely, legendary Moosapotamus' scan of the envelope part of the "Stompboxology" newsletter and a thorough scan of what Aunt Google spat out.

A good selection of all the necessary ICs is sitting around on my desk, breadboard ready, oscilloscope is on it's way, the guitar is tuned and waiting.

Funny thing 'bout the "Enveloope" pedal -> spot on, Mr. Hammer, thank you  I think I will write a humble letter to those who created it asking for a kick in the right direction, but I think you guys here already did exactly that.

I will put this together on paper: -> input buffer -> splitter -> filter -> enveloper -> chorus (maybe some easy-to-do circuit to boot) -> mixer -> output

Then I will breadboard it.

[Kipper4]

Good to know Karen. A 50/50 ratio on initial builds is decent. Probably better than I achieved.
Lots of us are untrained except by the wondefrul people here.
Your never too old though. I was told age 15 at a Navy careers interview I could never do anything like this because of colour blindness and look at me now, designing stuff with lots of help and occasionaly helping others with failed builds.
Maybe we can help you with some of your 50/50 later too.

as Larry says your gonna love it here.

[Mark Hammer]

Actually, an envelope-intensified chorus would be pretty straightforward.  Keep in mind that, until one blends in some delay, there IS no chorus effect.  This is why so many companies "bypass" their chorus pedals by sticking a single FET between the delay path and mixing stage, and turning it off.

In which case, an envelope-intensified chorus could easily use a photocell between the delay path and mixing stage.  It's not a changeover function,so much as a mixing-in function that only sounds like a changeover.  Strum harder, and the photocell gets illuminated by an LED, dropping its resistance and mixing in more delay signal.

[Kipper4]

Quick daft question

ref this;

"2. THIS! An Enveloope work-alike design
http://www.diystompboxes.com/smfforum/index.php?topic=67443.msg538459#msg538459"

Any suggestions on which fets I could sub for the 2N5462 used for switching I guess.
meantime I'll google the data sheet and compare to some of my common stock items.

Thanks
Rich


A quick search reveals I dont hold pnp fets.
Would a 2n5460 do?

[Kipper4]

Heres a rough out of an enveloped mixer idea.
Not verifed or breadboarded. Parts are subject to change.

[EBK]

Any suggestions on which fets I could sub for the 2N5462 used for switching I guess.
meantime I'll google the data sheet and compare to some of my common stock items.

Thanks
Rich


A quick search reveals I dont hold pnp fets.
Would a 2n5460 do?

2n5462 and 2n5460 are both p-channel depletion-type JFETs.  They do have different specs though....  Rich, if you get this thing to work, you'll be my hero. 

[Kipper4]

I'll order some 5460s next week and have a go Eric.
Have you tried it on the breadboard?

[EBK]

I'll order some 5460s next week and have a go Eric.
Have you tried it on the breadboard?

Haven't had the time or resources to try building it yet, sadly. But it seems like a good building block toward the Mood Shifter I've been envisioning.

[KarenColumbo]

Whoa!! Lotta brainstorm here!

Next step (after following three days of tedious job-realted skull@#$%ery):

1. Build the easiest chorus circuit that has a blend pot (and is 2399-based, since I acquired 30 pieces of that thang)
2. Get my head around the enveloper thing (like circuit #2 according to stompboxology)
3. reading ahead - thanks so much for all that additional info!!

[EBK]

and is 2399-based, since I acquired 30 pieces of that thang

....  I hope your source was reliable....  There are a lot of counterfeits and/or defective chips out there for that one.

[Kipper4]

Heres another idea. That's all it is right now.
Subject to changes. I think the vactrol leds need more work for one.