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treeclimber
Joined: Aug 09, 2010
Posts: 3
Location: New Zealand
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 Posted: Mon Aug 09, 2010 8:56 pm Post subject:
SK-1 Clock |
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Hi guys, I'm pretty new to circuit bending, but so far its been awesome fun. After messing around with a kids keyboard, my first project has been my beloved SK-1, and I'm really happy with it, so happy I sold my Alesis Micron.
Though I really enjoy the sounds I'm getting out of the machine at the moment, I'd like to add more layers. I have a few pieces of gear which don't have MIDI, but have digital clocks, so I thought that if I were able to digitally control the tempo of the SK-1 I could just set everything to a particular BPM, start everything at once and all my dreams would come true.
So I'd like to know if its actually possible to stabilize the tempo at all (during bends - right now its temperamental at best) and if so, how I could go about doing it. I'd love to cross bend my Kaossilator with it so it could share a clock signal for example.
By the way, having read through a few old threads, you guys get up to some awesome stuff. |
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electri-fire
Joined: Jul 26, 2006
Posts: 534
Location: breda nl
Audio files: 4
G2 patch files: 4
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| Posted: Tue Aug 10, 2010 7:43 pm Post subject:
Re: SK-1 Clock |
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| treeclimber wrote: | After messing around with a kids keyboard, my first project has been my beloved SK-1. /.../
If I were able to digitally control the tempo of the SK-1 I could just set everything to a particular BPM, start everything at once and all my dreams would come true.
So I'd like to know if its actually possible to stabilize the tempo at all (during bends - right now its temperamental at best) and if so, how I could go about doing it. I'd love to cross bend my Kaossilator with it so it could share a clock signal for example. |
This seems to be not an easy project.
Tempo feel on the SK-1 will remain somewhat temperamental. Especially when using the percussion (drum) channel with bends. However, when pitched way down the envelopes get stretched too, and loose their sense of attack, so Chord and Percussion patterns being off tempo isn't too much of a problem in my opinion.
Running an sk-1 and a Kaossilator from the same clock would probably not get you the results your after.
You could try to give them each their own clock , and run these clocks on the same voltage control. Sam_zen has a schematic for a clock for SK-1 with a 74LS** series IC that has voltage control AND a range offset. It gives you deeper and more stable pitchbend.
For the Kaossilator I recommend the Get-lo-fi clock, it's smaller and can be fit inside the case. With each having their own clock you could drive them on a common voltage. Then you can offset the SK-1 clock to get the tempo/pitch relation you want. (I may insert links here later).
Actually, I think pitching them both separately would give you the best sound. Leaving one pitch unchanged and freaking out on the other's pitchbend leaves some continuity in your music instead of going all over the place.
And you ain't done with bending I suppose. Adding a bent drum machine may get you the synchronized feel. The drum machines signals are synchronous to tempo, and dependant on the sound being played. You can use this as your master bender. Make sure to connect the Grounds from each device together for this to work.
Other idea: Convert several squarewaves from your bent instruments like your drum machine into a voltage ( with a simple to make R/2R DAC , and maybe some CMOS chips to slow the signals down) to pitch your Kaosslilator or SK-1. Check the Lunetta forum for tips and tricks. |
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electri-fire
Joined: Jul 26, 2006
Posts: 534
Location: breda nl
Audio files: 4
G2 patch files: 4
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| Posted: Tue Aug 10, 2010 7:49 pm Post subject:
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Oops, forgive my impoliteness. Welcome to the forum! 
And I love to see / hear demo's of circuitbent stuff (hint, hint). |
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treeclimber
Joined: Aug 09, 2010
Posts: 3
Location: New Zealand
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| Posted: Wed Aug 11, 2010 4:29 pm Post subject:
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Thanks for the leads Electri-fire. I actually referenced your website quite a lot while I was bulding my SK, it was a great help!
Probably the first question I should have asked was how does the clock on the SK actually work? Does it send a square pulse or a voltage? I did some noodling around yesterday with my Kaossilator, everything is horrifyingly small, and I'm also thinking that syncing/crossbending with a drum machine might be more useful, and, like you say I could use it as a master bender. I think I may get a 555 timer from GetLoFi then see how we go.
I'll probably post some images/sound files later on, though its nothing all that much - more or less just a tablebeast with extra patchbays, part mixing and an external mixing box for signals. |
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electri-fire
Joined: Jul 26, 2006
Posts: 534
Location: breda nl
Audio files: 4
G2 patch files: 4
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| Posted: Wed Aug 11, 2010 6:38 pm Post subject:
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| treeclimber wrote: |
Probably the first question I should have asked was how does the clock on the SK actually work? Does it send a square pulse or a voltage? |
If I remember right, the internal sk-1 clock is a sinus wave, though inside the CPU this is likely to be squared. It is a high frequency, above 1 MHz at least, maybe 4 MHz even, it's in the service manual somewhere.
Anyway, a 555 timer clock doesn't go fast enough, you need to get this: http://www.getlofi.com/?page_id=1302
to do this to the Kaossilator:
http://www.getlofi.com/?cat=243
http://www.getlofi.com/?p=2709
Maybe also for the SK1:
http://www.getlofi.com/?p=2189
But there I have had good results with Sam_Zen clock. Like I mentioned, you can easilly apply two voltages there, one "main" and one "range adjust".
http://www.xs4all.nl/~samzen/synth/sk1_data.html#hfosc
Sam's handwriting is a horror  , I posted some redrawings here:
http://electro-music.com/forum/topic-43419.html&highlight=
For info on bending drum machines the Burnkit 2600 site is THE place to be.
http://www.burnkit2600.com/ |
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