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Hollywood
Joined: May 22, 2012 Posts: 17 Location: Ireland
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Psyingo
Joined: Jun 11, 2009 Posts: 248 Location: Canada
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Posted: Tue Dec 04, 2012 10:59 pm Post subject:
Re: Sequencer by FRGMNT Subject description: A lurker looks for luck in Lunetta lunacy |
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Hollywood wrote: | I found this sequencer design by Frgmnt, but I don't understand how it works (http://frgmnt.org/) Frgmnt introduced me to the wonders of CMOS and my first self-built sound device, a hex oscillator feedback loop, which I use all the time. I've been learning quite a lot lately, so much from this here incredible forum as a lurker, and it's time to get building! I posted here as it is in the spirit of Lunettas for sure.
The sequencer is on page 3 of the attatched PDF, which is released under creative commons, and I hope the original designer doesn't mind! |
That sequencer is the combination of a binary counter (4060) and 8-1 multiplexer (4051). The 4060 has an internal oscillator for its clocking frequency which is set by pins 9, 10 and 11. q12, 13 and 14, the final 3 bits of the count, are sent to the multiplexer. the multiplexer can be thought of as an addressable rotary switch. q12, 13 and 14 supply the address for each pole of the switch from 1 to 8. the multiplexer switches which pot goes to the output.
...now this is where things look a bit strange. instead of using the pots as voltage dividers he has chosen to use them as variable resistors, for whatever reason and put an 18k to ground. this is probably not the most ideal use of a sequencer. the CV out will never go to 0V, and the overall range of voltage will depend on the pots being used.
i guess maybe this is to be used with vactrols?... |
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Psyingo
Joined: Jun 11, 2009 Posts: 248 Location: Canada
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Posted: Tue Dec 04, 2012 11:06 pm Post subject:
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oh, it seems he has an updated design http://frgmnt.org/w/wp-content/uploads/2011/01/8-Step-Sequencer.pdf. this makes more sense. as he has the previously unused legs of the pots tied to ground through a variable resistor. this allows you to tune it a bit, overcoming the issue of not having the cv achieve 0 volts as i mentioned previously. |
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Hollywood
Joined: May 22, 2012 Posts: 17 Location: Ireland
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Posted: Wed Dec 05, 2012 6:23 am Post subject:
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Thank you very much! I think that other version is actually older?! I'll pick up another 4051 later and get breadboarding. Frgmnt makes strange things anyway, so I'm very interested to see what it does. The TOB device on page 2 of that pdf is one of my favourite instruments ever, seriously dense fractal harmonic structures and Lunetta rhythms... lovely! Thanks again, it's appreciated. |
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Psyingo
Joined: Jun 11, 2009 Posts: 248 Location: Canada
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Posted: Wed Dec 05, 2012 6:57 am Post subject:
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Hollywood wrote: | I think that other version is actually older?! I'll pick up another 4051 later and get breadboarding. |
"Today Sergio from Mexico found an old documentation of a sequencer I made in 2007 for Piksel Festival. It contained several small errors, so here is the updated version of this nice 8-Step-Sequencer."
the original is from 2007, but it has been updated (without a date, I am assuming 2011 though, since thats the folder its in in the URL)
There is nothing very strange about that sequencer. It's a common sort of design, having a binary counter drive a multiplexer. it's good. Can be even better if you have a way of generating more interesting counts, like counting up or down, or ping-pong, or random. The 4060 can only count up, you would have to use another counter to get up and down... etc. |
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corex
Joined: Mar 02, 2010 Posts: 114 Location: Las Vegas
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Posted: Wed Dec 05, 2012 6:41 pm Post subject:
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For a more interesting counter, take a look at the 4516. |
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