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sneakthief
Joined: Jul 24, 2006 Posts: 569 Location: Berlin
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Posted: Thu Jan 10, 2008 4:21 pm Post subject:
Triangle to Saw waveshaper - anybody? hello? |
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ok i gave up on the pulse to saw, that's ok.
i think TH has one in one of his future-classic diy-synth books, but does anybody know of another?
the only thing i found was this - what the heck is going here? i know a cmos-switch is being used to choose the output, but i just want to use the waveshaper. how do i do that while omitting the 4066? i can't wrap my head around what's happening here:
_________________ Sneak-Thief - raw electrofunk |
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toppobrillo
Joined: Dec 10, 2005 Posts: 766 Location: oakland, ca
G2 patch files: 1
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Posted: Thu Jan 10, 2008 10:17 pm Post subject:
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look at the aries VCO and/or the Moog Sonic VI schematics for some hints- you just gotta invert one half of the triangle at the right time and add some offset to connect the 2 pieces together- unless you want a double frequency sawtooth.
josh |
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sneakthief
Joined: Jul 24, 2006 Posts: 569 Location: Berlin
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Posted: Fri Jan 11, 2008 4:09 am Post subject:
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i haven't made sense of the sonic vi schematics yet, but i'm peering at the Aries VCO layout - is this the one you're talking about?
if so, is that a triangle wave going into Q9? (at the beginning of the saw output section bottom right hand corner)
_________________ Sneak-Thief - raw electrofunk |
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toppobrillo
Joined: Dec 10, 2005 Posts: 766 Location: oakland, ca
G2 patch files: 1
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sneakthief
Joined: Jul 24, 2006 Posts: 569 Location: Berlin
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Posted: Fri Jan 11, 2008 10:08 am Post subject:
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topp: cool! many many thanks - that makes perfect sense. i appreciate the help.
i just finished my 3rd SN-Voice, this time it's a stand-alone unit. i'm adding Takeda's MS-20/Korg35 VCF and the Tri-Saw converter then calling it a day.
here's a pic of my SN-Voice before it got labelled yesterday:
_________________ Sneak-Thief - raw electrofunk |
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Danno Gee Ray
Joined: Sep 25, 2005 Posts: 1351 Location: Telford, PA USA
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Posted: Fri Jan 11, 2008 12:09 pm Post subject:
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Sneak-Thief, That looks Beautifyl! Nice build. |
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b-funk
Joined: Jul 17, 2007 Posts: 193 Location: Berlin
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Posted: Fri Jan 11, 2008 1:43 pm Post subject:
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hm, sneak, to be honest, it looks better without dymolabels
btw, good to hear that you had fun, and thank you for the link...
best wishes,
tobias |
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Tim Servo
Joined: Jul 16, 2006 Posts: 924 Location: Silicon Valley
Audio files: 11
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Posted: Fri Jan 11, 2008 2:17 pm Post subject:
Triangle to Saw waveshaper - anybody? hello? |
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Nice work, Sneak! I kinda like the "Stealth" (unlabeled) panel.
Tim (owns several stealth modules himself) Servo |
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sneakthief
Joined: Jul 24, 2006 Posts: 569 Location: Berlin
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Posted: Fri Jan 11, 2008 2:25 pm Post subject:
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I'm really curious how the SN-Voice will sound like with this Saw-waveshaper.
B-Funk & Tim: damn you minimalists! let me guess: i'm supposed to memorize what all the knobs and switches do - who am I, Stevie Wonder? heheheh. _________________ Sneak-Thief - raw electrofunk |
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toppobrillo
Joined: Dec 10, 2005 Posts: 766 Location: oakland, ca
G2 patch files: 1
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Posted: Fri Jan 11, 2008 3:24 pm Post subject:
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Quote: | I'm really curious how the SN-Voice will sound like with this Saw-waveshaper. |
probably just like any other sawtooth hehe
yeah i have labeled some of my own equipment with DYMO labels- never real happy with the look.
the building i work in is, apparently, according to several somewhat reliable sources, the building that the very first punch out-stick-on embossing label factory operated- this could be a rumour, of course, but there is evidence all over. Reaaally old labels stuck in the darndest places (still stuck!) with realy nice old fonts. wish i had an old labeler.
josh |
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b-funk
Joined: Jul 17, 2007 Posts: 193 Location: Berlin
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Posted: Fri Jan 11, 2008 4:26 pm Post subject:
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a minimalist? me? thin ice, thin ice...
ok, you´re right, i like very basic, stripped down design, but your point about the original moog modular sure is heavy-weight
nevertheless i like your work (this sn-voice, but also your modular and especially your midibox seq). very clean and reliable. not so chaotic like my "temporary" wirings and enclosures...
see you,
tobias
ps: MINIMAL KILLS MUSIC |
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bugfight
Joined: Aug 02, 2007 Posts: 188 Location: Arlington, TX USA
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Posted: Fri Jan 11, 2008 5:17 pm Post subject:
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sneakthief wrote: | ...et me guess: i'm supposed to memorize what all the knobs and switches do - who am I, Stevie Wonder? heheheh. |
hehe, just twiddle and random and see what happens...
looks good! |
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sneakthief
Joined: Jul 24, 2006 Posts: 569 Location: Berlin
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Posted: Mon Jan 14, 2008 5:34 am Post subject:
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topp - quick question: is that purple line with an arrow supposed to represent a square/pulse input? sorry to be so dense! _________________ Sneak-Thief - raw electrofunk |
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TheAncientOne
Joined: Dec 26, 2006 Posts: 144 Location: United Kingdom
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sneakthief
Joined: Jul 24, 2006 Posts: 569 Location: Berlin
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Posted: Mon Jan 14, 2008 10:50 am Post subject:
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TheProf - thanks that helps so much! The mechanics of the 4066 switching made sense in terms of the waveform selection, but your explanation of how it's also used to process the triangle makes perfect sense.
That said, also requiring a pulse wave output is a bit limiting since the SN-Voice only has 1) a triangle output and 2) a Pulse OR Noise output. (I guess there's no getting around that a tri-to-saw converter also requires a pulse for the comparator)
So... if I want to use the saw, I have to switch the SN to Pulse only and forgo all of the cool noise modulation possibilities. For example, yesterday I was using the triangle output as the main signal and using a mixture of the pulse and noise output on the exponential FM input.
This doesn't seem that exciting, but the digital noise can create some fantastic rhythmic sequences when clocked very low.
Here's an example of what I'm talking about, especially at 1:08min:
http://chromaticon.com/modular/SN-Noize-to-triangle-modulation.mp3
(LFO to Noise clock, Noise output to exponential FM input - I was tweaking the LFO speed & Noise filter) _________________ Sneak-Thief - raw electrofunk |
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TheAncientOne
Joined: Dec 26, 2006 Posts: 144 Location: United Kingdom
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Posted: Mon Jan 14, 2008 11:32 am Post subject:
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It might be possible to do a little trickery with a couple of comparators and a set/reset bistable to generate the square wave from the triangle, though this will add a bit of glitchiness to the switching.
logic flow would be like this:
'high' comparator set to just before peak voltage of triangle
'low' comparator set to just before minimum voltage of triangle
On first trip of high comparator, SET the flip flop
On first trip of low comparator, RESET the flip flop
Somewhere there is a trick, I think, for using 2 switches from a 4066 as a set/reset flip flop, but I can't seem to find it just now. _________________ Mike |
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ian-s
Joined: Apr 01, 2004 Posts: 2669 Location: Auckland, New Zealand
Audio files: 42
G2 patch files: 626
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Posted: Mon Jan 14, 2008 12:58 pm Post subject:
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sneakthief wrote: | the SN-Voice only has 1) a triangle output and 2) a Pulse OR Noise output. |
That seems like an advantage to me . I wonder what the saw shaper will sound like when you feed it noise. |
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sneakthief
Joined: Jul 24, 2006 Posts: 569 Location: Berlin
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toppobrillo
Joined: Dec 10, 2005 Posts: 766 Location: oakland, ca
G2 patch files: 1
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Posted: Mon Jan 14, 2008 1:50 pm Post subject:
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ok, apologies again- i didn't realize..
hmmmmmmmmmmm....
what is the relationship between the pulse and the triangle? for this circuit to yield a sawtooth you need a square that changes states when the triangle does, like the prof was talking about.. though that sounds rather a complex circuit to use here.
josh |
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Tim Servo
Joined: Jul 16, 2006 Posts: 924 Location: Silicon Valley
Audio files: 11
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Posted: Tue Jan 15, 2008 4:48 pm Post subject:
Triangle to Saw waveshaper - anybody? hello? |
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topp wrote: | ok, apologies again- i didn't realize..
hmmmmmmmmmmm....
what is the relationship between the pulse and the triangle? for this circuit to yield a sawtooth you need a square that changes states when the triangle does, like the prof was talking about.. though that sounds rather a complex circuit to use here.
josh |
Hey Josh,
You're right. The tri to saw shaper needs a square that changes states when the triangle "reverses" at its peaks. This is very tricky to do with comparators because you need to adjust the trip threshold as close as possible to the peaks of the tri. If the tri changes amplitude even a little it can mess you up. Still might be worth trying, but I don't think it'll be easy to get a "perfect" saw. One thought though: the shape of the saw is dependant on the phase relationship between the tri and the square. Because of this, you might actually come up with some "incorrect" results by changing the phase and width of the square. You'll get multiple peaks, or waves that sound just like a triangle, but are offset in strange ways around 0 (two positive peaks followed by two negative peaks, stuff like that). Might even sound neat or make a very interesting LFO, although you never know until you try. Still, you would have an animated wave that is easily voltage-controlled, so I'd think it might just be worth a shot.
Tim (offset in strange ways) Servo |
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toppobrillo
Joined: Dec 10, 2005 Posts: 766 Location: oakland, ca
G2 patch files: 1
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Posted: Wed Jan 16, 2008 9:10 pm Post subject:
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yeah, it could be cool to mess around with. if you just want to include a cool waveshaper, maybe one of Ian's designs would fit the bill. like the double-pulse waveshaper, for instance.
josh |
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sneakthief
Joined: Jul 24, 2006 Posts: 569 Location: Berlin
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Posted: Thu Jan 17, 2008 3:47 am Post subject:
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although the SN-Voice can give a 50% pulse for the comparator input of the tri-to-saw circuit, I'm eager to hear how the PWM will "glitch" the saw. _________________ Sneak-Thief - raw electrofunk |
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bubblechamber
Joined: Nov 04, 2006 Posts: 279 Location: NYC
Audio files: 1
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Posted: Wed Mar 12, 2008 3:25 pm Post subject:
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http://electronotes.netfirms.com/free.html
very bottom [Electronotes 129 Through-Zero VCO]
page 5 has the waveshaper for this. triangle and square to create pulse, sine and saw. you can skip the first amp the square hits and run a pulse directly into the FET. this might get you what you're looking for. it eliminates the PWM, I think, but if you've got that somewhere else anyway, it works. mine's still a little glitchy every other wave, but it's getting there. I've had to change a few values to get it working and I'd be happy to pass those along if anyone is interested. |
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sneakthief
Joined: Jul 24, 2006 Posts: 569 Location: Berlin
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Posted: Thu Mar 13, 2008 4:46 am Post subject:
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thanks bubblechamber - it'd be great if you could post the values you've used. _________________ Sneak-Thief - raw electrofunk |
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bubblechamber
Joined: Nov 04, 2006 Posts: 279 Location: NYC
Audio files: 1
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Posted: Thu Mar 13, 2008 12:09 pm Post subject:
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I should have it wrapped up this week. this is the only saw shaper I've built that really works right. |
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