Turkey Day SHOOTOUT Competition

[Perrow]

I can calm you with the fact that my build is a new layout for a known (and quite popular) circuit

[pakrat]

Thanks Perrow 

[Jdansti]

Thanks for the complements, guys. It was a fun build.

@Oldschoolanalog, yes I use Odius Max quite a bit (for guitar) .  I rescued a big plastic case from being trashed at the school where my wife is principal so I can cart him around more easily.  He might have a cameo role in my Turkey Day Shootout video.

Speaking of shooting, my wife owns quite a few guns and legally carries where she is allowed.  She's a better shot than I am too. I never miss getting the trash out on trash day!   

[Ronan]

Ok, I'll go next then...here's my entry - the Shiny Wobbly. (Shiny sort of finish, wobbly axle).

It is a low pass and all pass filter circuit, with six series filters, each pair is switchable between the two modes. The original design is by Jurgen Haible (RIP), the project name was varislope 36dB low pass filter/phaser, and it was designed for use in modular synths.

I came across this circuit a few months ago, but then revisited it after Dino (Digi2t) put up his Tau pipe phaser build, and J. Haible had designed the layout for the Tau pcb, so I was again drawn back to his website. Then I saw how versatile the phaser section was, and wondered how it would go in a wah enclosure.

The basic filter circuit was copied, and the complex LFO and control circuits of the original were omitted. The modifications were minimal, the input stage was altered to suit guitar input, and the output was padded to suit guitar levels. The filter circuit is unusual in that it uses jfet buffers as well as the inbuilt LM13600/LM13700 buffers.

The end result is a pedal capable of synth-like sounds. It has a nice clean and very versatile phaser section, the feedback (resonance) signal can be inverted before being fed back to the beginning of the filter stages, and the filter output can be inverted before being mixed with the dry signal. There is a wet/dry pot that also affects the tonal variety of the phase output, and there is an overall volume control on the output.

One departure from "standard pedal practice" is that the power supply is regulated +/-15V, derived from a 15V AC wall wart which feeds a voltage doubler inside the pedal, followed by standard LM317/LM337 regulators.

Schematic:



Vero overlay
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Build pics:
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In the video clip, you will notice the pedal works back to front, as in, heel down for max treble or upwards swing of the sweep. This is because my first wah pedal worked backwards and I have wired every wah pedal since then to work the same. I was pretty nervous too, sorry about that, and got some of the wording wrong, (vibrato/tremelo, delay/reverb) them's the breaks.

I'm very happy with the actual sound quality of the circuit, its a great design, thanks to JH. I was going to do some mp3 clips, but I feel the video covers nearly all of the sounds reasonably well. If parts of it sound "over the top", this circuit can easily be tamed down into subtleness with the feedback and mix knobs.


Trials and tribulations - the bias current control circuit for the LM13700's that I conjured up didn't work, and despite all precautions, three of them got destroyed, two at first, then another one died a few days later, probably from the previous trauma. Then one of the replacements turned out to be making hiss, so it got replaced too. I ended up with a very basic, but safe, bias current control and now it works fine. The new wah enclosure kit gave me some problems too, the base plate was not a good fit, so I made a new one, and the axle for the pedal was a sloppy fit (hence the name "wobbly") and I had to ream the pedal hole for the splined end of the axle otherwise I would have broken something trying to get the axle to sit flush. Other than that, it was smooth sailing, but took a long time to build. (The wah kit was from mammoth and I bought it from them rather than Small Bear because it weighs less and overseas shipping is much cheaper.)

[haveyouseenhim]

Damnit! I've been knocked down one more place in this comp
I was angry till your Australian accent soothed my rage

I'm really impressed by the wiring. 10/10

[Jdansti]

Excellent job, Ronan!  So many great sounds from one pedal!  I expected to hear "Industrial Disease" there toward the end. Sounds and looks marvelous!

After seeing and hearing the entries so far, I'm glad I'm not a judge. This is going to be like watching world class atheletes finish a race with only a hundredth of a second difference between each of their times! (Of course I'll be trailing some minutes behind!)

[pakrat]

Wow, another excellent entry. I really like the liquid tone you're getting there, and the clean finish looks great. I must agree with John that this will be a tough one to judge. Great job Ronan!

[garcho]

Bravo! Fairly simple circuit for how friggin' cool it is! Love me some 13700

Nothing wrong with15v! Every other electronic device I own has its own DC adaptor, why not pedals?

[deadastronaut]

@ian:  that sounds really great!!!. ...love those swirly sounds ...very nice!

i don't blame you for being a bit nervous...i never speak on videos.. ....but hey thems the rules right!.


good luck to ya'll.........

[Mustachio]

Oh man that sounds awesome Ronan! Man the sound was so thick and lush! I want something like this for sure, will have to look into it later.

You got 3 of the lm13700's working together! Thats awesome. I was having trouble just using the second side of the lm13700 in my Mutron Project. It seemed like when I jumped one side of the ota to the other it had less of an effect. Seemed like with the amp bias's connected together (1-16) cut the effect in half. So Im guessing what feeds that needs a boost. Looks like you got the bias control set up great ill have to look and see what ya did!

After seeing the projects posted so far I have no chance at all! haha but that's ok I mainly wanted to help out the forum and get the contest active! You guys are great!

[Perrow]

Oops, got a little bit of blues there...

It's ok for this time, but don't let it happen again   

Really nice sound you got from that thing, I thought about leaving a snide remark about the complexity of the controls, maybe something about the builder needing a manual to adjust the controls, but I wouldn't endorse such a thing just to help my cause, and I guess the Americans here seen enough negative campaigning lately

[midwayfair]

Treadles! Awesome work, Ian. Sounds really cool.

[oldschoolanalog]

Nice pedal & presentation Ian!  
The judges are in for a lot of difficult decision making. Seems each entry makes it more and more difficult.  
BTW; I LOVE the concept of video presentations. Really gives a good feel for the entries. Much better than just a couple of pretty pictures.

PS: There are a couple of contestants that I consider "heavyweights" (you guys know who I am talking about... ). I eagerly await their presentations.

[slacker]

Amazing stuff so far folks, great to see so many great new designs, looks like the competition is doing exactly what the judges hoped it would.

For my entry I decided the the competition didn't have enough rules so I invented some of my own.
1. Build a fuzz pedal with 5 knobs
2. Use a quad opamp
3. No diode clipping

The result is the SuperVixen distortion, fuzz, octaver, noisemaker. It's my homage to people like Tim Escobedo, Devi Ever and Zachary Vex.



Guts


Build docs, schematic and vero layout are here supervixendocs.pdf

Youtube proof of life

I'll try and do some soundclips if I get time, the youtube video was only going to be a test to see how my phone picked up the sound, but it turned out alright so I decided to use it.

Enjoy

[Jdansti]

Sounds great, slacker!  A lot of versatility without a bazillion components!  Another fine entry!

[davent]

To my beat up ear, sounds of Queens of the Stoneage and Grinderman in there.  Nicely done!

dave

[haveyouseenhim]

It reminds me of some of the fuzzes used by older punk bands. Sounds petty good.

[digi2t]

Sounds like a Great Destroyer and a Skyripper made a baby! 

[garcho]

Bravo Slacker! Glad to have another one of your projects bouncing around. Textured, fun, f'd up, sounds great!

Stoner idea #42033754: Make a multi-fx unit with the Turkey Day Shootout builds. Maybe more of a rack unit type of thing. 

[digi2t]

Bravo Slacker! Glad to have another one of your projects bouncing around. Textured, fun, f'd up, sounds great!

Stoner idea #42033754: Make a multi-fx unit with the Turkey Day Shootout builds. Maybe more of a rack unit type of thing. 

I'll take a haul on that reefer, and MIDI'fy it all. Ppppffffffffffffff.... yeah baby, now THAT'S what I call a fire!