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sndbyte
Joined: Jun 26, 2009 Posts: 119 Location: sf
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Posted: Sat Sep 04, 2010 10:43 am Post subject:
VCO for Lunetta: CD4046 vs the 555 chip |
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I want to build a VCO for my Lunetta board now. I have both the CD4046 chip and a 555 chip.
I was wondering which would be best to add. I'm running all of my chips at 5v (with the exception of a WSG filter at 9v).
The VCO will be used when I add a 4017 sequencer later.
Any suggestions as to which chip I should use? I was planning on having just one VCO on this board.
thanks!
Chris |
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tjookum
Joined: May 25, 2010 Posts: 360 Location: Netherlands
Audio files: 26
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Posted: Sat Sep 04, 2010 12:29 pm Post subject:
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I have the 4046 on my breadboard and it works very well, good range and minimal components make it an unbeatable combination for me. If you want to use a 555 I would suggest using the CMOS 7555 wich has a lower power consumption.
Another great simple solution is the YAVO:[url] http://electro-music.com/forum/viewtopic.php?highlight=yavco&t=33937
[/url]
another option if you just want to use the sequencer to gate signals:
http://deathlehem.com/php/download/file.php?id=521&mode=view
This way you can plug in any signal and gate it according to the programmed sequences.
Personally I dont like VCO's in lunetta, and only use mine in combination with the triangle lfo or r2r. A big part of the fun of lunetta's for me is flexibility and a open mindset to music, why have a VCO when you can experiment with gates, shift registers and all kinds of mayhem?
[/url] _________________ There he goes. One of God's own prototypes. A high-powered mutant of some kind never even considered for mass production. Too weird to live, and too rare to die.
Hunter S. Thompson
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fluxmonkey
Joined: Jun 24, 2005 Posts: 708 Location: cleve
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Posted: Mon Sep 06, 2010 8:29 am Post subject:
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fluxmonkey wrote: | technically, the 4046 oscillator as usually built is an "RCO"--resistance controlled oscillator. to control it w/ a voltage, you have to replace the timing resistor w/ some kind of voltage-to-resistance widget, like a vactrol. the 555 family can be directly controlled by a voltage... |
apologies, i mis-spoke... 4046 PLL obviously can be used as a VCO _________________ www.fluxmonkey.com Last edited by fluxmonkey on Wed Sep 08, 2010 10:54 am; edited 1 time in total |
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richardc64
Joined: Jun 01, 2006 Posts: 679 Location: NYC
Audio files: 26
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Posted: Mon Sep 06, 2010 11:29 am Post subject:
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tjookum wrote: | Personally I dont like VCO's in lunetta, and only use mine in combination with the triangle lfo or r2r. A big part of the fun of lunetta's for me is flexibility and a open mindset to music, why have a VCO when you can experiment with gates, shift registers and all kinds of mayhem? |
That's what I tried to say at that other forum. I'll try to stir up that kettle again when things have settled down over there. _________________ Revenge is a dish best served with a fork... to the eye |
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richardc64
Joined: Jun 01, 2006 Posts: 679 Location: NYC
Audio files: 26
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Posted: Mon Sep 06, 2010 11:42 am Post subject:
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fluxmonkey wrote: | technically, the 4046 oscillator as usually built is an "RCO"--resistance controlled oscillator. to control it w/ a voltage, you have to replace the timing resistor w/ some kind of voltage-to-resistance widget, like a vactrol. the 555 family can be directly controlled by a voltage... |
Another method is found in Thomas Henry's X-4046 VCO or the Mega Percussive Synth, both of which can be found here http://electro-music.com/forum/forum-148.html or with more info at Scott Stite's http://www.birthofasynth.com/Thomas_Henry/TH_main.html. Definitely not in the so-called "Lunetta Spirit." _________________ Revenge is a dish best served with a fork... to the eye |
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DGTom
Joined: Dec 08, 2008 Posts: 211 Location: Adelaide
Audio files: 3
G2 patch files: 1
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Posted: Mon Sep 06, 2010 5:45 pm Post subject:
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The 4046 is a VCO. Its linear, but it works with a +ve voltage on pin 9. Another good referance;
http://www.cgs.synth.net/modules/cgs31_digital_noise.html
The timing resistors set the range.
The X-4046 is a really cool approach, because trying to bootstrap the CV input into something sensible is nigh on impossible.
Why have gates & shift registers if you can't experiment with modulating the speed of the clocks driving them? working with fixed clocks (manually variable) & even divisions all the time doesn't seem very flexiable or open minded to me |
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tjookum
Joined: May 25, 2010 Posts: 360 Location: Netherlands
Audio files: 26
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Posted: Tue Sep 07, 2010 1:31 am Post subject:
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Quote: | Why have gates & shift registers if you can't experiment with modulating the speed of the clocks driving them? working with fixed clocks (manually variable) & even divisions all the time doesn't seem very flexiable or open minded to me Wink
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Ok ok, there are uses for them and like I said especially analog signals can be a nice change from the squares. But modulating the speed of the clock can be sort of done with a nand gate and another slower clock, or a 4053 or a 4066 switch. Im just saying that the concept of a modular system containing VCO,VCF,VCA's is not what youre looking for in a lunetta.
But...If it works for you, go for it! Having fun, building and making music is all that really matters _________________ There he goes. One of God's own prototypes. A high-powered mutant of some kind never even considered for mass production. Too weird to live, and too rare to die.
Hunter S. Thompson
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Rykhaard
Joined: Sep 02, 2007 Posts: 1290 Location: Canada
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Posted: Tue Sep 07, 2010 4:38 am Post subject:
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I myself enjoy the contrast between gradually changing pitches as opposed to immediately changing pitches. There, I have no troubles using VCOs in my noise machines. The 'restriction' that I stay away from, is the pre-determined amount of scaling FOR the pitches. Heck with that. Everything that I'm making on my noise machines is in the Key of Naught. |
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Draal
Joined: May 18, 2010 Posts: 308 Location: Oak Park, IL
Audio files: 5
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Posted: Tue Sep 07, 2010 2:40 pm Post subject:
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richardc64 wrote: | tjookum wrote: | Personally I dont like VCO's in lunetta, and only use mine in combination with the triangle lfo or r2r. A big part of the fun of lunetta's for me is flexibility and a open mindset to music, why have a VCO when you can experiment with gates, shift registers and all kinds of mayhem? |
That's what I tried to say at that other forum. I'll try to stir up that kettle again when things have settled down over there. |
I hear ya both! _________________ Zontar Prevails! |
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DGTom
Joined: Dec 08, 2008 Posts: 211 Location: Adelaide
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Posted: Wed Sep 08, 2010 12:31 am Post subject:
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Its abit of a non-argument... work in whichever way suits you & the sounds you make; which for me is primarily Voltage Controlled.
tjookum wrote: | Im just saying that the concept of a modular system containing VCO,VCF,VCA's is not what youre looking for in a lunetta. |
I agree, but, thats just one concept of a modular system. I never use the "Moog Method" of subtractive synthesis... I do use ALOT of CMOS however |
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Rykhaard
Joined: Sep 02, 2007 Posts: 1290 Location: Canada
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Posted: Wed Sep 08, 2010 4:10 am Post subject:
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DGTom wrote: | Its abit of a non-argument... work in whichever way suits you & the sounds you make; which for me is primarily Voltage Controlled.
tjookum wrote: | Im just saying that the concept of a modular system containing VCO,VCF,VCA's is not what youre looking for in a lunetta. |
I agree, but, thats just one concept of a modular system. I never use the "Moog Method" of subtractive synthesis... I do use ALOT of CMOS however |
I basically grew up around the 'Moog Method' with synths, since about '75, with the additive strongly thrown in later. So it's hard to separate the brain from that decades of influence.
When it comes to the CMOS side of it though - everything's wide open whether it's results hit the VCF end of things before a VCA (IF a VCA exists) or not.
Modulation of just about anything tho, to me, is key. |
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jnuaury
Joined: Feb 28, 2008 Posts: 161 Location: chicago
Audio files: 9
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Posted: Wed Sep 08, 2010 10:15 pm Post subject:
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i do love the 4046 but my favorite uses for it go beyond lunetta-like simplicity
ray wilson has a CV mod for his WSG which works well. you of course dont need to build the WSG but you can throw a 2N5457 tranny over the timing resistor/pot in a 40106/4093 oscillator to make it a VCO... really cool _________________ az/gde
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gasboss775
Joined: Jan 02, 2016 Posts: 217 Location: Scotland
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haebbmaster
Joined: Aug 27, 2016 Posts: 40 Location: Windenreute, Germany
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gasboss775
Joined: Jan 02, 2016 Posts: 217 Location: Scotland
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Posted: Fri Apr 07, 2017 10:13 am Post subject:
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haebbmaster wrote: | I recently built VCOs by Mark Shaner, at 5V
looks very similar to that by gasboss775
CV response is good, the output transistors can be omitted |
My circuit is pretty much the same idea with the addition of the 5K6 resistor to widen the output pulse, though this has the unfortunate effect of flattening the relationship between frequency and CV. This type of thing tends to be less of an issue in Lunetta setups, though. |
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elektrouwe
Joined: May 27, 2012 Posts: 143 Location: Germany
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Posted: Mon Apr 10, 2017 1:23 am Post subject:
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gasboss775 wrote: | ....the 5K6 resistor to widen the output pulse, though this has the unfortunate effect of flattening the relationship between frequency and CV. |
yes, and the 2nd "unfortunate effect" is that both circuits use current drive
for the current sink transistor. For exponential ( V/oct) behavior it's important to voltage drive the transistor with a low impedance voltage divider (<= 1k to GND) for proper Vbe control.
This is done in the classic circuit which is now about half a century old.
btw: the first saw tooth oscillators that use this principle ( with neon tubes as "Schmitt-triggers" are now 100yrs. old ... |
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gasboss775
Joined: Jan 02, 2016 Posts: 217 Location: Scotland
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Posted: Mon Apr 10, 2017 7:26 am Post subject:
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elektrouwe wrote: |
btw: the first saw tooth oscillators that use this principle ( with neon tubes as "Schmitt-triggers" are now 100yrs. old ... |
There is a guy on Muffwiggler who has built fairly sophisticated noise makers based on neon bulb oscillators, its something I've been meaning to try out, but I need to build a high voltage power supply first ( another thing on the to do list! ) |
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