[Pics] Dualish Logic Drive: Combo Blue Box, PWM, Uglyface, Idiot Wah, Booster

[Processaurus]

Here's this mutant blue box I've been working on for a while,  its the blue box based thing where the two channels you pan between get the logic signal  processed by two Tim Escobedo circuits, and then get mixed together.  One side gets the PWM, and the other gets the Ugly Face.  Theres some photo resistors hooked to the CV input on the 555.  Each channel can choose whether it gets the fundamental, 1 or 2 octaves down, or a ring modulator type sound, which is the fundamental and 2nd octave down feeding a XOR gate.  The XOR gate is the same logic the beloved MS-20 uses for its ring modulator on one of the oscillators.  So then everything gets mixed, and goes to the Idiot Wah.  Then this goes to a fixed 10x gain stage, and out.  The bypass switching is done remotely by the little pedal, using the 4053 schematic available at geofex.com.  There is a switch (the tough guy switch) on the red side that turns the 555 into an oscillator, which feeds another XOR gate along with whatever octave is selected on the rotary switch, for a 1 bit digital ring mod.  Lastly there is a momentary switch I threw in at the last minute that feeds back the output to the input TSA-style through a 10k resistor, because it sounded cool.  With that switch you can make a good variety of glitchy circuit bent sounds without anything plugged in.


The graphics are printed on photo paper and stuck on with spray adhesive, which really works well if you spray both the paper and the box.  Much clear coat after that.  Durability wise I'm not to worried, because its more of a table top device that doesn't get stomped.  I found those great long handled switches in the trash at my work  along with the momentary switch, which has a nice snap action.  Construction wise I was the most excited about getting the rotary switches to match up with the graphics, if anyone else try this with the Lorlin switches, they click 30 degrees between each position.  There are little holes for the locater tabs on the pots and rotaries, that got covered up by the paper thankfully.  They're nice to have, and (may?) help keeping things from getting loose and spinning around.  Oooh, and the LED is a bicolor type, driven by two of the spare schmitt inverters.  The whole thing only draws 16mA, if you can believe it.  Too bad there's no room for a battery.


The best discovery soundwise of the project was how cool the PWM sounds processing one channel, that would make a great mod to a more toned down blue box clone, and opens up a hole new palate of synth tones for the price of 1 schmitt trigger IC.

Much thanks to Tim Escobedo for his amazing circuit snippets, and RG Keen for the CMOS switching article, and an unknown mad scientist at MXR...

[bluesdevil]

WOW..... now that's cool!!

[Peter Snowberg]

Beautiful!

[Phorhas]

AWSOME!!!

nuff said

[bwanasonic]

Alright - Make with the sound clips! 

Kerry M

[Pushtone]

Nice!

I  totally LOVE the recycled PCB as box decoration. 

[Gripp]

Awesome!!!
Sort of what I was thinking about but in a modular way, mine is way behind though.
Really nice work!
Sound clips ei?
Another question. I've been toying with the xor as well, looking at both the circuit snippets octave and the modified ms-20 schematics (http://www.analog-synth.de/synths/ringmod/digital_ringmodulator.htm ), breadboarding using both a CD4070 or a CD4030, tying all unused inputs to ground etc but it still doesn't work right. It should give an octave when using it the circuit snippets way but it doesn't. How, exactly did you implement the xor part? Unused cmos pins, square wave dc position, RC thingys etc? As far as I've understood, the squares hitting the xor needs to be in quadrature (90 degrees apart) for it to work its best. Somebody correct me if I'm wrong.
Best!
Pelle G

[RaceDriver205]

I dont know how it sounds, but that looks smooth!

[dano12]

That is fantastic on so many levels. Intriguing circuit ideas, plus an awesome job on the enclosure--it just looks so cool.

You made theList http://beavisaudio.com/theList/

[Mark Hammer]

LOVE the "Tough Guy? Yes/No" function.

One of these days, I need to label a distortion control "Can you handle it?" with "Damn straight" at one end and "Not tonight, I have a headache" at the other.

I love "integrated" pedals, in which several different circuits are combined in a manner to achieve something greater than the sum of the parts.  Nice work, and good inspiration to others.

[Processaurus]

Thanks a lot, everyone.  Its cool being able to show stuff like this to people that'll get it.

Awesome!!!
Sort of what I was thinking about but in a modular way, mine is way behind though.
Really nice work!
Sound clips ei?
Another question. I've been toying with the xor as well, looking at both the circuit snippets octave and the modified ms-20 schematics (http://www.analog-synth.de/synths/ringmod/digital_ringmodulator.htm ), breadboarding using both a CD4070 or a CD4030, tying all unused inputs to ground etc but it still doesn't work right. It should give an octave when using it the circuit snippets way but it doesn't. How, exactly did you implement the xor part? Unused cmos pins, square wave dc position, RC thingys etc? As far as I've understood, the squares hitting the xor needs to be in quadrature (90 degrees apart) for it to work its best. Somebody correct me if I'm wrong.
Best!
Pelle G

I don't know about the phase thing you're talking about, sounds interesting though, I really like the MS-20's ring mod sounds
The first link is actually where I got the notion.  I used the XOR to get a waveform like this, kind a ringy mix of the fundamental and the 2nd octave. 


I tapped off the fundamental, which was a normal logic level signal (0-~9v square wave in this case, no DC bias or RC or anything), at the point where it was feeding the 4013 flip flop, and ran that to pin 1 on the CD4070 quad XOR gate chip.  The second octave down went to pin 2, and the output of the gate is pin 3.  Pin 14 connected to +9v, and pin 7 to ground, and if you aren't using the other XOR gates, ground the other gates inputs: pins 5,6,8,9,12,13.  Leave the unused outputs unconnected.

Feeding the fundamental and 1 octave down squarewaves to the XOR just gives you the same 1st octave down 90 degrees out of phase (one cycle of the fundamental), which may be useful for some things, but will sound identical to the original 1 octave down.  I don't know what you get when you route intervals other than octaves (like you were doing on your rocktave divider you were telling me about) through the XOR along with the fundamental, probably something pleasingly synthy...

Dano12, thanks for putting me on "the list".

Mark, a friend was telling me about this custom amp he saw (might have been made for one of Zappa's kids) where the volume was labeled "What You Want".

[MartyB]

Wow what a cool creation!  Like Kerry M said we need soundclips!

[Gripp]

Thanks!
Very clear explanation. I'll have to go back to the lab with this.
Well, my main motive for using the xor was to have the possibility of a nice octave up.
The ring stinger, when used as an octave fuzz (feeding fundamental to both inputs), works so well. The octave up that results is very prominent.
I wanted this in a square wave setting, dividing for octave down and xoring fundamentals, octaves and fifths for "understandable"  (including octave up) results or choose some other interval and get a more classsic ring mod.

[swt]

Hey Gripp...the pwm also says ring mod, did you made something with that also?. Are you going to make a schem of this?, at least the ring mod, etc?. it's really cool. thanks for sharing!

[Gripp]

I had nothing to do with this, its all Processaurus.
Me and him seem to share a fascination for square wave treatment though
I'm still experimenting with my setup (pwm and xor's on breadboard etc) and would very much love to hear some sound clips of this beautiful creation.
Best!
Pelle

[Processaurus]

Hey Gripp...the pwm also says ring mod, did you made something with that also?. Are you going to make a schem of this?, at least the ring mod, etc?. it's really cool. thanks for sharing!

Hi, there is a 1 bit digital ring mod in there, I don't have time to make a schematic, but basically the 555 in the uglyface gets the audio signal disconnected from pin (the 555 timer's reset pin) and instead that pin gets held high, which turns it into a free running square wave oscillator.  That gets routed to one input on one of the extra XOR gates.  The other input to that XOR gate is always being fed by the square wave (derived from your instrument) that was selected with the rotary switch even when the ring mod is disconnected, and was tapped off before it got used to feed the reset pin on the 555.  The output of this XOR gate is the disgusting ring mod sound. 

The only problem is that the 555 continues oscillating after your note stops, and the XOR lets that through.  Some more circuitry could take care of that, like using one of the leftover schmitt triggers from the PWM to change an envelope signal into an on/off logic compatible voltage, then another inverter to make it go high when you're playing, and low when you're not. Then that can get used to control the reset pin of the 555.

This wasn't a very thought out feature, just something noisy to do with the parts that where there already.

[birt]

this is really wonderfull. it looks great, has great ideas in it. i would love to hear some clips