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theshaggyfreak
Joined: Oct 29, 2006 Posts: 48 Location: Centreville, VA
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Posted: Wed Nov 11, 2009 7:17 pm Post subject:
50240 top octave + diy sequencer |
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So, now that I'm starting to get my head wrapped around the whole DIY synth thing, I'm starting to play what to do with these two mk50240 chips that I inherited from my uncle. What I think I'd like to do is pair a sequencer with them as well as add a filter. While I'm pretty sure on what I'm going to go with as far as a filter, I'm not entirely sure what would be the best sequencer circuit to put in. There just seem to be so many out there!
I guess what I'd like to try and achieve is something akin to a tb-303 as far as functionality goes but I honestly don't need something that complicated. To be honest, I'd be happy with just a simple pattern sequencer. I've seen some very simple sequencers using a 4017 but I'm not sure that I could make that apply in this situation. I appreciate any suggestions! _________________ Shaggy
http://www.pureshift.com
http://www.bsodmusic.com |
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slabman
Joined: Sep 01, 2005 Posts: 102 Location: UK
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Posted: Thu Nov 12, 2009 11:37 am Post subject:
different kind of sequencer? |
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Shaggy - if I'm not misunderstanding your post, the answer to your 'how do I get there?' question is probably 'don't start from here'. The 4017-type sequencers generate monophonic voltage, gate and trigger control signals to control a classic analogue signal chain of vco, vcf, vca and enevelope generator. The TOG chips you have are designed to generate a simultaneous top octave of squarewaves to feed a chain of dividers in a polyphonic organ type of instrument. You could create some kind of sequencer based instrument but it would be hard to emulate a TB303. Instead you'd be more likely to be simply gating a bunch of squarewave notes on and off. If you wanted to make a kind of noise sequencer, you could arrange to have the gated individual note outputs feed into a simple digital ring modulator. Different combinations of notes would generate different timbres. Does this make any sense? |
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theshaggyfreak
Joined: Oct 29, 2006 Posts: 48 Location: Centreville, VA
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Posted: Thu Nov 12, 2009 12:14 pm Post subject:
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Yes, that does make sense. I wasn't sure whether or not I could some how use a 4017 but what you're saying makes sense. I guess what I'm looking for is a circuit that I could use to trigger a series of notes. _________________ Shaggy
http://www.pureshift.com
http://www.bsodmusic.com |
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Uncle Krunkus
Moderator
Joined: Jul 11, 2005 Posts: 4761 Location: Sydney, Australia
Audio files: 52
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Posted: Thu Nov 12, 2009 1:21 pm Post subject:
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Does a TOG have all notes for the octave present as soon as it's powered/clocked?
A sequencer might be possible by putting each of those outputs through it's own conditional divider.
For each step, you could have the choice of activating 2 or 3 (etc) gates which are switched to certain top octave notes, along with another setting to tell how many octaves to divide down by. Sounds like a whole heap of rotary switches I know, but it could possibly be done with some muxes and some nifty data control.
I actually have a TOG somewhere which I reckon would be way cool to play with. Must find the time. _________________ What makes a space ours, is what we put there, and what we do there. |
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theshaggyfreak
Joined: Oct 29, 2006 Posts: 48 Location: Centreville, VA
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Posted: Thu Nov 12, 2009 2:11 pm Post subject:
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Uncle Krunkus wrote: | Does a TOG have all notes for the octave present as soon as it's powered/clocked?
A sequencer might be possible by putting each of those outputs through it's own conditional divider.
For each step, you could have the choice of activating 2 or 3 (etc) gates which are switched to certain top octave notes, along with another setting to tell how many octaves to divide down by. Sounds like a whole heap of rotary switches I know, but it could possibly be done with some muxes and some nifty data control.
I actually have a TOG somewhere which I reckon would be way cool to play with. Must find the time. |
That's kind of what I was thinking. I figured that I should do something with these things. I guess I'll have to start bread boarding and play around. _________________ Shaggy
http://www.pureshift.com
http://www.bsodmusic.com |
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richardc64
Joined: Jun 01, 2006 Posts: 679 Location: NYC
Audio files: 26
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Posted: Thu Nov 12, 2009 3:51 pm Post subject:
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You'd need a sequencer that outputs a number of bits at each step: 4 for the note select (with only 12 states being valid,) and 2 for, say, 4 octaves. Then you'd need a 12-to-1 mux to select which note to send to a 4-bit counter and a 4-to-1 mux to select the octave.
Instead of rotary switches, the CV output of a more conventional sequencer could be fed into an ADC. The steps would be inherently "quantized."
Or am I talking out of my ass again? _________________ Revenge is a dish best served with a fork... to the eye |
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Uncle Krunkus
Moderator
Joined: Jul 11, 2005 Posts: 4761 Location: Sydney, Australia
Audio files: 52
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Posted: Thu Nov 12, 2009 7:53 pm Post subject:
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richardc64 wrote: | Or am I talking out of my ass again? |
Well, it sounds good to me! _________________ What makes a space ours, is what we put there, and what we do there. |
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slabman
Joined: Sep 01, 2005 Posts: 102 Location: UK
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Posted: Fri Nov 13, 2009 4:36 pm Post subject:
Phase locked loop |
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The sequenced output from the TOG could be fed into a 4046 pase locked loop. By varying the timing in the loop, you could get back the ability to have slides between notes |
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theshaggyfreak
Joined: Oct 29, 2006 Posts: 48 Location: Centreville, VA
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slabman
Joined: Sep 01, 2005 Posts: 102 Location: UK
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Posted: Tue Nov 24, 2009 5:21 am Post subject:
Bliptronic 5000 |
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Possibly - but it would cost you way more than $49.95 to build! Modding one of these into a synth module might be fun and useful though. |
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electri-fire
Joined: Jul 26, 2006 Posts: 536 Location: Dordrecht NL
Audio files: 4
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Posted: Mon Jan 04, 2010 9:11 am Post subject:
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Datasheet : http://www.alldatasheet.co.kr/datasheet-pdf/pdf_kor/98048/ETC/MK50240.html
Your 50240 produces a 13 note chromatic scale from a stationary clock frequency.
You could use a CMOS 4051 8to1 multiplexer to select one of 8 notes you want.
Each note from the 50240 goes to an input of the 4051, the output of your note would be at pin 3.
You need one oscillator to drive your 50240, and wich of the 8 inputs at the 4051 is sent to the output is determined by a binary code at the ABC pins.
With three oscillators at the ABC pins you get a nice semi random sequence, with overall pitch determined by the pitch of the oscillator in at the 50240.
That said, you could build a sequenced little synt with more easy obtainable IC's, like in the schematics on the milkcrate page, and keep the 50240 as a transposer (selecting the note with a multiple rotary selector).
http://milkcrate.com.au/_other/sea-moss/
I have aquired a biggish load of IC's myself, some datasheets are at http://www.electri-fire.com/filetransfer.htm (files for TP)
So if you could list the stuff you got from your uncle we might develope some cool devices from our joint collection and swap some stuff.
. |
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electri-fire
Joined: Jul 26, 2006 Posts: 536 Location: Dordrecht NL
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G2 patch files: 4
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Posted: Mon Jan 04, 2010 11:14 am Post subject:
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richardc64 wrote: | Am I talking out of my ass again? |
I just grasped what you were suggesting, and it has a lot in common to my idea. No ass talking whatsoever, so let's specify the practical side some more...
richardc64 wrote: | You'd need a sequencer that outputs a number of bits at each step: 4 for the note select (with only 12 states being valid,) |
With the 4051 8-to-1 mux I opted for 8 notes per octave. Can you suggest a suitable 12-to-1 multiplexer chip?
richardc64 wrote: | and 2 bits for, say, 4 octaves. |
The 50240 does only one octave. So to get the octaves you could use these bits to divide the input frequency of the 50240 by two or four. With some gate, erm.. NAND or AND? Need to think about that later to prevent ass talking myself... I'm tired, and just recently into this stuff.
richardc64 wrote: | The CV output of a more conventional sequencer could be fed into an ADC. The steps would be inherently "quantized." |
Now this could be a Baby-10 (or Baby- sequencer, = 4017 step sequencer with pots to tweak output voltage.
Three bits would suffice for 8 notes, 4 bits would go up to 16. How about simply having an on-off switch for each step to select just two octaves?
. |
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electri-fire
Joined: Jul 26, 2006 Posts: 536 Location: Dordrecht NL
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Posted: Mon Jan 04, 2010 11:28 am Post subject:
Subject description: On the Bliptronic 5000 LED Synthesizer |
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That Bliptronic 5000 LED Synthesizer is a potentially fun thing to hack.
You get 8 parallel running gate sequences, and each step could be considered an 8-bit number to be converted into a voltage. Also the on-off's from each step could be AND/NAND gated for "Boolean Sequencer" use.
Danno-Gee-Ray got one for his birthday recently, and bought another 'cause liked it.
So Danno, if you read this, please open them up to check if they're "solderable". |
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Danno Gee Ray
Joined: Sep 25, 2005 Posts: 1351 Location: Telford, PA USA
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electri-fire
Joined: Jul 26, 2006 Posts: 536 Location: Dordrecht NL
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Posted: Mon Jan 04, 2010 4:36 pm Post subject:
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Danno, you're THE DUDE...
Looks solderable to me. Ooohh... now I want one too.. |
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electri-fire
Joined: Jul 26, 2006 Posts: 536 Location: Dordrecht NL
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RF
Joined: Mar 23, 2007 Posts: 1502 Location: Northern Minnesota, USA
Audio files: 28
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Posted: Wed Jan 06, 2010 11:56 am Post subject:
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UPS tells me two of those (Bliptronc 5000) will be delivered to my house tomorrow...
Over the past couple weeks I've been searching for how others have hacked those...and not coming up with anything very encouraging.
Hard to resist trying, though....
bruce _________________ www.sdiy.org/rfeng
"I want to make these sounds that go wooo-wooo-ah-woo-woo.”
(Herb Deutsch to Bob Moog ~1963) |
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electri-fire
Joined: Jul 26, 2006 Posts: 536 Location: Dordrecht NL
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richardc64
Joined: Jun 01, 2006 Posts: 679 Location: NYC
Audio files: 26
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Posted: Wed Jan 06, 2010 3:06 pm Post subject:
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electri-fire wrote: | Can you suggest a suitable 12-to-1 multiplexer chip? |
There ain't no such animal. And anyway, I meant to say 13-to-1 mux. You could use two 4051s for a 16-to-1 mux, with 3 of the inputs grounded. These would produce 'rests' if selected.
Or, a single 4051 could choose among 8 notes a sequence would contain, rather than a full chromatic scale. But I see you thought of that already.
Quote: | With the 4051 8-to-1 mux I opted for 8 notes per octave.
richardc64 wrote: | and 2 bits for, say, 4 octaves. |
The 50240 does only one octave. So to get the octaves you could use these bits to divide the input frequency of the 50240 by two or four. |
I was thinking the octave divider(s) would come after the note selection. Either way would work, I suppose. _________________ Revenge is a dish best served with a fork... to the eye |
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