Developing my CMOS organ concept...

rosch · Joined: Oct 03, 2009 Posts: 164 Location: germany

i'm interested too. needless to say i had this (or similar) thought too when playing with the apc and cacophonator. i just doubt i have skills enough to develop such an organ.
but isn't the 40106 cheap enough to take one for each tone (maybe 2 corresponding tones, just in different octaves to reduce crosstalk) ?

how many input channels could possibly be used for a mixer (with or without pots)? are there limitations also?
such are the 'questions without answer' here... so i thought i better start small.
and having full polyphony, even if it's just an octave and no filter / envelopes it would imo outweigh not being able to switch globally octaves / sound settings like in regular organs.

anyways, i'm interested in weird organ sound, even with smd.

synthmonger · Posted: Thu May 27, 2010 7:16 am Post subject:

[quote="Rykhaard"]
Bingo! I forgot about this exactly. Not - is there crosstalk between the inverters across the chip, so that 4 oscillators would not be a good idea?
/quote]

You can use two inverters on both sides of the chips at either ends to avoid cross talk. Keep the middle one input pin grounded and everything will be fine.

Rykhaard · Joined: Sep 02, 2007 Posts: 1290 Location: Canada

[quote="synthmonger"]

droffset · Posted: Thu May 27, 2010 3:44 pm Post subject:

If the 40106 oscillators are just for the top octave oscillators would the crosstalk mess up the the 4040's input? The 40106s probably won't be heard at all, and the output of a 4040 is always a clean 50% duty cycle. Then you can set the 40106s to be two or three octaves above what you want and tune them by listening to one of the 4040's divisions.

Tuning all 12 tones sounds labour intensive, I'd consider having one main oscillator and getting creative with divisions to get your 12 tones.

I guess a downside would be the inability to do pwm on the voice...

Has anyone tried Ray Wilson's key matrix scanner?

How many octaves do you want to do? Maybe start small.

I'll try it too, hehe.

synthmonger · Posted: Thu May 27, 2010 4:13 pm Post subject:

droffset · Posted: Thu May 27, 2010 4:51 pm Post subject:

Still need to try your 40106 VCO Synthmonger, forgot about that one.

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Oops, My Bad, I forgot that Taylor didn't want to go the top-octave route. 12 oscs it is.

But just for reference, this page shows the divisions a top octave chip would do. http://www.organservice.com/crm/topdividers.htm

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synthmonger · Posted: Thu May 27, 2010 5:38 pm Post subject:

I need to update it with buffers and things. It'll be a bit before it's fine tuned enough for public use ;d