Posted: Mon Aug 11, 2008 9:39 am Post subject:
schematic: +v pins as CV IN pins on CMOS with SCHEMATIC
This trick which has been floating around in some of these threads for a bit now (i have seen jnuary and RF both mentioning the successful use of it), and for those who havent seen it or tried it,well i highly recommend it.
after working up a giant mess of breadboard stuff today, , i was trying to plug a cv into an oscillator with having to make a big vco on breadboard, when i remembered the CV to +v trick.
wow. it works great with a 40106 and i am sure it would work with others. to me it doesnt really sound like a starve at all though you do get some weird results (in a good way)
this might not be the direction you want to take for precision BACH concertos but for lunetta stuff, i think it works a lot better than a vactrol on a 40106.
(and easier too)
anyway. i just wanted to make a thread about this so no one would miss it and so maybe we could get some ideas bouncing around about how to add features like offset, hi and low limits, etc. one thing i'd like to be able to do for sure is shift the whole CV signal down an octave or two and i think this can be done with offset but i am never sure.
lets see i think i tried home rolled ones and also tried a vactec of some kind. my problem was it didnt seem to respond to as wide of a range. that could be my memory serving me wrong but it seemed that if i went up into super high freqs i didnt get much of a reaction (i think i posted once about that even...looking for ways to offset the signal)
anyway, i know it is possible because i even have a schematic i DREW that i used a vactrol to a 40106 but i really think this voltage trick is better for my quick and dirty use.
Posted: Tue Aug 12, 2008 7:10 am Post subject:
schematic
Here is a schematic showing exactly what i now have on my breadboard except The 40106 values are NOT what i have on my board (they are really just shown to show that the 40106's are being used as oscillators of some kind...insert your own values for low hi or ultra hi)
also, take the outs from wherever you wish. (since this R2R only has 6 ins and there are tons of outputs to choose from)
if anyone has any method on choosing which outs to take (is there much difference between out 1 or out 4 on the 4094? arent they just the same but delayed from each other?
i added a range pot to my CV in on the 40106 which helps to go from very low pitch to super high.
anyway, endless noises with this setup. I AM LOOkING FOR any ADVICE On how to integrate more stuff (4051,etc)
thanks
EDIT: schematic fixed (opamp pins)
ENDLESS NOISE FIXED.pdf
Description:
great cv source for weirdness if you just take the out of the opamp and plug it into a vco.
wow, that looks a lot more involved/refined than what i tried.
i had several oscillators built on a single 40106 chip (outputs mixed together thru resistors). on the same breadboard, i also had a 4093 wired as 4 oscillators, each one gating the next... pretty large cap values, so it was slow. then i just disconnected the power from pin 14 of the 40106, and fed the output of the last 4093 oscillator into the 40106 power pin. instant freq out!
not sure i'd call it CV or "modulation", more like brute force, but a very cool trick.
Joined: Jan 07, 2007 Posts: 368 Location: 127.0.0.1
Posted: Sat Aug 16, 2008 11:47 pm Post subject:
Another option is to use a 4024 or LM3900 as a pulse-counter, so that the voltage ramps up for each pulse it receives. Adjust how many pulses and you could have some sort of rhythmic modulation.
Joined: Jan 07, 2007 Posts: 368 Location: 127.0.0.1
Posted: Sat Aug 23, 2008 11:21 pm Post subject:
loss1234 wrote:
can you explain that a little more?
i dont think i have ever used a pulse counter
A pulse counter is a circuit which outputs a voltage, this voltage level depends upon how many pulses are counted. A typical application might be a chip putting out zero volts with a zero count. It could count up to, for instance, 24 pulses. So for a +12V supply would mean that for each pulse input, the output increases by 0.5V. At the 24th pulse it would have ramped up to 12V and reset to zero.
This is another percussion application I learned from Thomas Henry, via his "Electronic Drum Cookbook". He calls it a "Beat Follower", his counts from 0 to 127. I played with it on breadboard once long ago, and have meant to make some more versions of such for some time. Also I was reading about this in some LM3900 application notes, along with the other hundreds of things those chips can be used for.
Joined: Feb 28, 2008 Posts: 161 Location: chicago
Audio files: 9
Posted: Sun Aug 24, 2008 1:48 am Post subject:
ive been away from the internet for most of this month!
cant believe this i missed this thread...
would you mind pointing me towards RFs post on this? i dont think i searched for the right keywords
this technique has been one of my favorite things to do since i started fiddling with electronics but i could never find any projects people have done with it (there HAS to be somebody who did this back a couple decades ago....)
using an op amp to add an offset has been something that although makes things more "proper" ive found makes things maybe more complicatedly than it needs to be
i like how mystical the circuit seems when you dont need that extra power cable... of course this perspective has nothing to do with practicality
i also hardly use frequency pots for oscillators on the 40106 when using the power input as CV method - theres so much variation you can get by altering the voltage that i like fixing the values of the oscillators and adding a pot to adjust the current of the incoming voltage and sometimes a second pot wired as a voltage divider
i havent found the perfect values yet but i like using three inverters at audio rates wired to one output and three at subaudio to another so i can derive funny audio or a more complex CV from any CV source
one pot and three jacks is a panel friendly layout than having 6 frequency knobs thrown in i guess it all depends on whether the voltage input is a extra feature or the main function....
i think in my situation, the more pots the better, because it is now becoming almost a CV BRAIN/sequencer/PSUEDO RANDOM DEVICE.
LET ME EXPLAIN:
first of all, on my model, the opamp pins 2 and 3 are flipped. so i took the output from the opamp and i sent it to a breadboard that has
1. the 2nd 40106 which is about to be controlled VIA CV.
2 BUt i also took another output from the CV/power area (the same junction that goes into pin 14 of the final cmos chip. here i simple put a jack
3. This means that i have a lot more options for controlling my modular.
a. i can take the 40106 output and use it TO FM MODULATE things. or i can use it as an audio source, or to modulate the Filter at audio frequencies, or just as a CV source wherever. and with all the pots on the panel, you can easily turn the module into a sub audio monster or a screeching random note high frequency bomb! it really makes me feel like i can play it like an instrument.
also, the non audio output, the straight CV output, can obviously be used to control a VCO, or can be fed into a comparator to get gates out of it, or can be used with, well, any thing.
I also added some switches that (monetary switches) interrupt the 4094, flip the resets High on the 4015, and select 2 different data or clock ins on the 4015 or 4094. and when you start getting those buttons going, wow...the infinite weirdness just keeps going and going..
i must say this is now my FAVORITE control modular. if hooked up to mults and done right, i have been able to get stuff that sounds like a sequencer or others that sound like appregiators, or trills, or crazy stuff!
the key is feeding the two outputs to different places, and really getting creative with how the modulation comes into play.
IF i do a pcb of this, i would also like to add some CV INS onto the board
nothing fancy, just maybe some vactrol control of the clocks and maybe a 4016 to give cv control of turning the resets on and off, etc.
Joined: Feb 28, 2008 Posts: 161 Location: chicago
Audio files: 9
Posted: Mon Aug 25, 2008 1:07 pm Post subject:
as promised...
this is a one chip circuit using a 4093
the clips werent made to sound musical or cool but just provide simple interaction between a CV source and the chip
two are just a stepped random voltage (always between 0 and 5 volts) powering the 4093 once without a "starve" pot and once with it adding resistance (no knob tweaking)
the other one uses an audio source (sine wave vco) for the power input causing the 4093 to act as a waveshaper i set the starve pot so it would mangle the sine wave but let you still identify the "notes" playing (which are of course random) at the beginning of the clip the rate of the random notes is slow and then later i turn the rate knob up a bit and then lighten up on the starve effect near the end
lunettaSH.mp3
Description:
stepped random voltages
Filesize:
655.95 KB
Viewed:
1954 Time(s)
lunettaSHstrv.mp3
Description:
stepped random voltages and a pot used to starve the current from the CV to the chip
Filesize:
721.46 KB
Viewed:
1971 Time(s)
lunettarandosine.mp3
Description:
sine wave vco playing random notes plugged into power input
Posted: Mon Aug 25, 2008 3:53 pm Post subject:
samples
Ok
these samples are either of the my ENDLESS NOISE schematic with ONLY the output of the +V cved 40106 as the audio OR my modular being controlled by both the CV OUT jack AND the +v CVED 40106 audio out at the same time.
some of the clips experimented with having the audio from the 40106 AND the audio from the CVED vco go through an XOR
or some other combos i cant remember.
i got some great interactions though. i want to add more reset, reload, and input change toggles (not on schematic) to this.
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