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Ruebezahl
Joined: Mar 09, 2014 Posts: 104 Location: Taiwan
Audio files: 4
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Posted: Sat Aug 02, 2014 7:31 pm Post subject:
Another Modular Drum Machine Subject description: (Work in Progress and Question) |
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So i am planning on this project recently, which is a Modular Drum Machine, the Sequencing done mostly by simple CMOS Logic.
The Project which inspired me most was this Thread by Psyingo: http://electro-music.com/forum/topic-52786.html&postorder=asc
I want to built pretty much a similar machine like his. Not necessarily the same voices or all the same details, but his concept is very close to my idea. We will see where my project is leading me in the end, and if the outcome is still similar
However, i opened this thread to 1. make my plans public, so there might be suggestions what to do better, and 2. to ask questions, since i am still a beginner, and this project will be more advanced than previous ones.
So my plan so far:
Clock: For the clock generator i wanted to use one 74HC14-Chip, since i used it in different projects before. I want to let it oscillate on subsonic frequencies and afterwards i want to put the output through a 4040 so i have different outputs of which each of them puts out half of the speed of the other. That should be easy.
PROBLEM: Well what the 4017 puts out are Gates right, so its high for a certain time. But i think most Drum Voices are fed by a trigger signal, right? Psyingo used a so called "Gate to Trigger"-Converter, using 4503-Chips. He left schematics and it looks really easy to build. But since he built them with inputs and outputs seems like they are just an option, and one could also want gates to feed into the drum voices. also i wanted to know, is a Pulse Stretcher something like the opposite of afore mentioned "Gate to Trigger"-Converter? The existence of this module also left me thinking that having a gate imput into the drum voices is desirable sometimes. my theory would be: the drum voices, fed by a trigger signal will play in a drum kind of way, short and having a somehow defined envelope. fed by a gate the same voice will just play as long as the gate will be high. am i right?
Logic-Parts: Afterwards the signal can be chained through some basic Logic Chips like And, Or, Xor etc. Feel free to suggest what kind of Chips could result into funny rhythms.
Voices: Didn't think much about this yet. But since i like the Sound of Psyingos Machine, i most likely will use the same or similar Voices. Also feel free to suggest any Drum Voices with low Part Count and beginner friendly. I don't need a lot of buttons to fine tune the voices later, i rather have a few buttons wich are fun to play with.
I found this Twin-T Circuit which looks easy to built, so i might implement it: http://electro-music.com/forum/viewtopic.php?highlight=twint&t=28541
So thats it for the first, i will update as soon as i have more detailed plans or first results.
Thanks for your Help,
Ruebezahl |
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synaesthesia
Joined: May 27, 2014 Posts: 291 Location: Germany
Audio files: 85
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Posted: Tue Aug 26, 2014 10:45 am Post subject:
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With regard to the PROBLEM you mentioned: I built something remotely similar once, including four drum voices similar to those used at http://www.paia.com/ProdArticles/syndrum.htm, but running with the op-amps in the drum circuits at 9V. I triggered them from TTL logic running at 5V using a 74LS06 with a pull-up resistor to 9V at the inverter output and it worked fine. If you run your logic with VDD at V+ and VSS at V- for the drums, you could try any inverter (like the 4049) or buffer (like the 4503) with high sink/source capability.
Regarding the trigger signal: In my circuit I used a monoflop to generate very short pulses (ms) to trigger the drum circuits. I guess that a long trigger signal coming directly from a counter output would not work in many cases. Depending on the actual drum circuit, you might get two triggers (at the rising and falling edge) or nothing at all until the trigger goes high again.
Regarding voices: a twin-T is a must-have in my opinion.
Regarding the "funny rhythms": looking for cool ideas here myself. Have a look at the post from PHOBoS about the Euclidean rhythm generator. |
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Ruebezahl
Joined: Mar 09, 2014 Posts: 104 Location: Taiwan
Audio files: 4
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Posted: Thu Sep 18, 2014 4:53 pm Post subject:
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Thanks for your answer! I was out of town for a while, and just saw it.
My Progress so far:
For the Drum Voices i chose a Hip Bass Drum, a Synbal and a Syntom, all from threads here in the Forum. I might add some basic Twin-T and maybe a very easy Hi hat.
Hip Bass Drum
Synbal & Syntom
I already etched the PCBs for all three, and also finished populating the Bass Drum. So it could work now - maybe. whats missing, is the trigger signal...
I built the MFOS-Wallwart Power Supply, and now have a +-15V Power Supply. But a Trigger Generator running on this voltage, like a 4049, would also generate 15v-signals, right? I fear this could be too much for some of the drum-circuits. For the Bass Drum it says "10V is best, but +5V will do". Do i need to power the trigger circuit seperatly?
Also it seems the Drum Circuits all expect different Trigger-Voltages, since the Syntom and Synbal are actually designed for the use with Drum-Pads. I need to find a way to work around that. Probably i need to adjust their circuits so they can accept higher Trigger-Voltages. _________________ https://soundcloud.com/ruebezahl |
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