Looking for some kind of auto-wah DIY

[Earthscum]

I've been looking around all over the net for something that I assume is called an "auto-wah". I've found a couple layouts, but there's really no decent description and none I've found have soundclips. (ok, maybe one did, but I don't think I was really impressed with it).

Basically I'm looking for a circuit to play around with that I can get a reactive "wah" out of. Also, I'd like to be able to get the wah clean, not likewhat I've been seeing (fuzz box with OP Amp filters). What I would also like is to maybe be able to  use the same circuit to be able to go from clean, deep tone at a light pick to a full-out LM386 sounding scream... in other words use it to replace a manual blend  circuit maybe. I watched a clip of the Schaller Bow Wow Yoy Yoy and was impressed by it ALOT, and will probably build a clone of that for manual wah.

BTW, I'm a bassist, as well when I DO play guitfiddle, it's tuned to Dflat. Guitar box should work fine, as long as I can get my bass signal through without losing the bottom end. My amp is badass at lowend recovery, but it's not magical, lol. Any ideas? I'd like it to be as simple as possible without sacrificing option possibilities so I could possibly incorporate it into other effects.

Thanks!
~Dave

[mth5044]

Did you look into the DOD440? GGG has a clone.

[Earthscum]

I'll have to look at that again. I have schem for it, but didn't know what it did.

What are some other names for these pedals? It's kinda frustrating. The only pedals that I can tell what they do by schem's is phasers. I see alot of pedals with descriptions that baffle me as to what they do... is it a phaser, flanger, tremolo, auto-wah? WHAT THE HELL DOES IT DO?!? Thanks to everyone who has ever posted a product demo on YooToob... definitely helps.

Is the Gargletron a pedal like what I want, or is it some kind of reactive tremolo?

[mth5044]

I think auto-wahs are some times called envelope filters, or a type of envelope filter. Not sure what the gargletron is.

Also, here is mellowtones go on the DOD440, which he calls the MEEP.

http://www.youtube.com/watch?v=x2uuiUlDShc

Is what what you are looking for?

[Wales]

I just built the Nurse Quacky and am quite happy with it. It is relatively a simple build as well.

[Earthscum]

mth5044, that's one that I'm looking for... that has a nice sound to it. Nice wide sweep.

Nurse Quacky, eh? Is Dr. Quack a variation?

The last time I did anything with an envelope filter was probably about 18 years ago. I wasn't that impressed because it just acted like a flanger/phaser. We were broke Jr. High kids who couldn't afford a whole lot, so if a pedal wasn't gonna get used for more than one song, we didn't waste the money on it, and multi-effects processors were still in racks and way out of our league (I remember drooling over the first digitech and alesis modules in town...)

I'll keep looking around. Gonna go check out some of the 440 demos.

[brett]

Hi
I like the MXR envelope filter.  Available at tonepad.com.  The schematic and PCB look difficult, but it's not hard.  But there IS one bit of a "trick" with the biasing of one of the inverters, because the standard value for one resistor is a bit "off".  Check out the build reports for details (maybe I wrote one those build reports?).
just my 2c

[Earthscum]

So, I checked a couple out... so far from what I can hear, I really like the Dr. Q/ Nurse Quacky the best. The MXR was ok... modded ones were better, but they sounded just like the Q's. I wasn't impressed with what I could find of the DOD (I feel the way about DOD as some people do about Boss... just something that's not there... it's like having a metal singer with no attitude).

So, next question: could I sub a TL082 for the LM358, and how much change would there be in the sound? Would the fet smooth out the tinny sound without killing the effect by chance? I've been on the FET kick lately... it really does seem to be a way to polish a turd (ie, FETs actually make my DeanZ Autograph sound better than it really is). Also, how about the TL072, or 4558? Basically, is there a specific reason for the LM358, or is it just a regional availability thing?

[Earthscum]

Hah! Scrounging around (I KNEW I saw a "Dr. Quack" somewhere!) I found Orman's Dr. Quack, which answered my question about the OP Amp, mostly. Guess I'll experiment a bit.  http://www.muzique.com/schem/quack.gif

So, is  each side of the OP Amp acting as a filter, or is one acting as a variable filter? Reason I ask is because I wouldn't mind trying a pair of LM386's and maybe be able to add drive controls for integrated distortion that can easily be kicked in and out. If one acts as a variable filter, cana LM386 be modded into it's place and a 741 in place of the other? Figure I'd ask before getting too far into it and frying an IC (I know they are cheap, it's just more of a pain to have to go get another one, lol).

[Mark Hammer]

Read this to get you started: http://hammer.ampage.org/files/Autowah.PDF

[Earthscum]

Muhahaha!! Thanks a bunch! Decent guides that actually explain things in context (and at a rational vocabulary level) are hard to find concerning circuits... and I don't thing Google helps that matter. We need a search engine just for audio DIY'ers... like what Alta Vista used to be for hackers.

[mth5044]

Muhahaha!! Thanks a bunch! Decent guides that actually explain things in context (and at a rational vocabulary level) are hard to find concerning circuits... and I don't thing Google helps that matter. We need a search engine just for audio DIY'ers... like what Alta Vista used to be for hackers.

We do, it's right at the top of this page, before profile and after help     

Mark Hammers stuff is great. A lot of GEOFEX is on the average DIYer's reading level too. It's hard to not get your technical questions answered between these few sites.

[Thomeeque]

 I've fallen in love with Xotic Robotalk2 effect, it's the most delicate auto-wah I've heard (imo much better than first Robotalk).. If somebody has an idea, how to DIY this effect (just channel A) or even had schemo for this one , please let me know..

btw. Paul Jackson Jr.'s demo videos are amazing!

[moosapotamus]

The original Robotalk was nearly identical to the Maestro Filter/Sample & Hold, so the Robotalk 2 might be based pretty closely on that... minus the S&H part.

~ Charlie