Saturday, July 11, 2009

RAINBOW SYNTH

i just finished this piece a couple of days ago.

the original circuit was from a rather generic toy keyboard from the nineties. all it consists of is a tone generator with i think 3 octaves including sharps. i think it also had some demo songs but i left them out. i took the signal coming from the keyboard, fed it through a comparator, ran it through a frequency divider, ran that through a filter and finally to a little headphone amp. the signal also triggers a one-shot that triggers an attack release generator that modulates the cut off frequency of the filter. sadly though, i built the one shot out of a 555 chip so it does click when the volume levels arent adjusted properly with an external amp. next time i'll use an op-amp or something. the one shot time can be adjusted with the "gate" pot. this kind of works as a sustain. the main vco can be mixed with two sub voices from the frequency divider. with voice one all the way up, it is the only one you can hear. all the way down and its between voice 2 and 3. there is also a 4 step sequencer that is tunable and can be triggered either by an LFO or the main VCO. both of which can be divided by 1, 1/2, 1/4, 1/8, and 1/16 by another frequency divider. the VCO coming to the sequencer divider is actually 1/16 of the main VCO. the one shot can also be triggered with either the LFO or the VCO.


the case was made from an old touch and tell toy that i had in my collection. i added the keys the two big blue holes with all the functions and a big battery compartment. the lettering are dry press decals with lots of clear coat(notice the glaze?). the keys are color coded. this thing was supposed to be an homage to the resistor but the blue is a little too bright.


the lfo speed can be modulated manually too. there is also a resonance pot, envelope depth pot, a fine tuning pot for higher tuning, a coarse pitch bend, and a volume pot. all in all i am pretty happy with this keyboard despite all the grief it was giving me last week. i still have two more of these VCO chips and i think they will be put to similar use.

8 comments:

  1. this piece is beautiful and i don't think you should take less than 500.00 for it.

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  2. Could you please tell me your ebay user name?

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  3. its noystoise_one but i dont plan on selling anything on ebay any time soon. eventually www.noystoise.com will be a real website with a really real store...thanks anyway though

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  4. great cant wait. your keyboards make me incredibly happy

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  5. I was wondering why you run the main signal through a comparator?

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  6. thanks, the comparator is to square up the audio signal so it can be easily divided. otherwise the frequency divider just acts like a really bad equalizer.

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  7. This has to be one of my favorite Synthesizers Ive seen in a long time!


    -Louie

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  8. omg! this is so amazing. i'm really sorprised to found someone who can make such beatiful things.
    Do you sell them? i'm from Argentina, but i'm really interested on your synthesizers! anyway, congrats!!

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tanner