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DIY Stompboxes => Building your own stompbox => Topic started by: markr04 on September 05, 2004, 09:38:20 PM

Title: Envelope Follower layouts anyone?
Post by: markr04 on September 05, 2004, 09:38:20 PM
Hi. I was really wanting to build this:
http://www.geocities.com/tpe123/folkurban/fuzz/snippets.html
(11th one down, "Phuncgnosis")

It's too advanced for me to read (like where are the pin-outs of the ICs, which diodes to use, and many more). But it looks like it would be simple enough to build, if I had a PCB layout. The sample sounds great too.

Can anyone point me in the direction of a decent, kinda-simple envelope follower PCB/Schematic/parts list sort of thing?

Many many thanks!
Mark
Title: Envelope Follower layouts anyone?
Post by: sir_modulus on September 05, 2004, 09:46:37 PM
There are lots of classic envelope filters. The easiest one is a EH (Electro Harmonix) Doctor Q. You can find Nurse Quacky, an implementation of the Dr.Q @  ROG. (http://www.runoffgroove.com) For something a bit more complex, you can try the JEN HF modulator at  GGG  (http://www.generalguitargadgets.com/) or the MXR Envelope Filter @  Tonepad  (http://www.tonepad.com/projects.asp?projectType=fx)Thats my advice.
Hope that helps,
Title: Envelope Follower layouts anyone?
Post by: sir_modulus on September 05, 2004, 09:52:22 PM
do you want to figure out the phuncygnosis? I'd make a great beginner project to learn about finding out about components and making a perfboard layout for yourself. It's just a suggestion, but if you want to learn furthur read onwards. First, you need some diodes eh? Well it says si (silicon). That means you can use all small silicon diodes (like 1N914 and 1N4148 etc... (those are real common)). Next when you want to find out the pinout of a opamp, you type one into google, and go to the first PDF result. It gives you a few options, for instance, the TL072. Go to google and type TL072 and click on the datasheet (link #2). You see, it shows the pinout for all the TL072's (you find the one you have, and read the little opamp symbol, and find out which lead is which on your opamp). Then you use this to make a little perf layout.

Hope that helps,
Title: Envelope Follower layouts anyone?
Post by: markr04 on September 05, 2004, 11:22:17 PM
Quote from: sir_modulusdo you want to figure out the phuncygnosis? I'd make a great beginner project to learn about finding out about components and making a perfboard layout for yourself. It's just a suggestion, but if you want to learn furthur read onwards. First, you need some diodes eh? Well it says si (silicon). That means you can use all small silicon diodes (like 1N914 and 1N4148 etc... (those are real common)). Next when you want to find out the pinout of a opamp, you type one into google, and go to the first PDF result. It gives you a few options, for instance, the TL072. Go to google and type TL072 and click on the datasheet (link #2). You see, it shows the pinout for all the TL072's (you find the one you have, and read the little opamp symbol, and find out which lead is which on your opamp). Then you use this to make a little perf layout.

Hope that helps,

It does help greatly, thanks! Yes, I'd prefer to figure this one out.

This is the way I interpret that opamp datasheet:
1. signal out
2. ground
3. signal in
4. Vcc-? (ground?)
5. not used?
6. not used?
7. not used?
8. power in

I'm sorry. I don't try to be this ignorant. Am I close in my interpretation? Which pins are actually used? All 8?

One more thing: "Vx" is in 4 places. Does this mean to plug those 3 in the lower part to the Vx in the little 'power cluster' up top?

Again, thank you very much!
Title: Envelope Follower layouts anyone?
Post by: RLBJR65 on September 06, 2004, 09:11:48 AM
Opamps confussed me at first too.

Looking at the triangle sections (which represent opamps in schematics) you will see u1a and u1b, (u is normaly the letter used to to denote an op amp in parts lists) so there are 2 opamps sections used and when you see 1a and 1b it is calling for a single IC with 2 opamp sections.

The TL072, etc. listed are dual opamp's IC's so the pins for u1a would be  - 2   + 3    1 output and the pins used for u1b would be + 5   - 6    7 output. Pin 8 would be V+ and pin 4 would be ground.

Hope this helps, This project is on my list as well, I realy like Tim's simple approach and have built several other projects of his.
Title: Envelope Follower layouts anyone?
Post by: sir_modulus on September 06, 2004, 10:20:04 AM
your a bit off. You see, there are two triangle things. Those are opamps. (U1A and U1B) The reason why they are 1A and 1B and not 1 and 2, is because the circuit calls for a dual opamp (a small 8 pin IC with 2 opamps inside) There are a bunch of standard ones (ask if you want me to name some). TL072 is a pretty standard one (they are all interchangable as most common dual OA's have the same pinout). The pinout is as follows:

Opamp 1:
output: pin 1    
minus: pin 2
plus:    pin 3

Opamp 2:
plus:    pin 5
minus: pin 6
output: pin 7

Common:
VCC(+): pin 8
VCC(-) : pin 4

so in Phuncygnosis, you hook up pins 1,2, and 3 to the first triangle as shown. Then pins 5,6, and 7 to the second one as shown. pins 4 and 8 are unconnected.

P.S. check point VR. to make sure that it's about half of nine volts (it's called a voltage divider circuit (see above the filter for the small circuit))
Title: Envelope Follower layouts anyone?
Post by: RLBJR65 on September 06, 2004, 03:13:49 PM
Hmmm! 4 and 8 not connected? I assumed you always had to power up the IC! and when it wasn't shown you used the V supply and ground. This may clear a couple of non working projects off my bench!!!

Thank's sir_modulus
Title: Envelope Follower layouts anyone?
Post by: Hal on September 06, 2004, 03:31:51 PM
Quote from: RLBJR65Hmmm! 4 and 8 not connected? I assumed you always had to power up the IC! and when it wasn't shown you used the V supply and ground. This may clear a couple of non working projects off my bench!!!

Thank's sir_modulus


no........you _do_ have to connect power.  I think he was saying that its unconnected - unralated to - the rest of the project, or something to that effect....
Title: Envelope Follower layouts anyone?
Post by: markr04 on September 07, 2004, 01:56:15 PM
Thank you all so much for sharing your knowledge. I'm so glad I found this forum!