cv controlled sequencer/programable switch/analog wavetable

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Luka
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Post by Luka » Tue Feb 09, 2010 6:10 pm

definately worth pursueing

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the bad producer
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Post by the bad producer » Wed Feb 10, 2010 2:01 pm

I too think this is worth pursuing! I'm not so hot at following the maths, but I can make things, and I think I'd like to make this (either the first circuit, if it is ready, or whatever else it may happen to become)

Charlie

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falafelbiels
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Post by falafelbiels » Wed Feb 10, 2010 2:32 pm

O yes please do persue. I'm going to stick that CV->binary addressing in a panel anyway and see what this turns out like. I was planning on several binarily-addressed sequencers anyway and would like as many options for driving them as possible. I had some LM3914 for this for a while but couldn't quite figure out how to use them.

:tu:

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wetterberg
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Post by wetterberg » Wed Feb 10, 2010 5:36 pm

PURSUE!
I think we can really rally behind this idea and get creative as a group; the first muff-wiggler forum modules, perhaps?

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falafelbiels
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Post by falafelbiels » Wed Feb 10, 2010 6:06 pm

YES! with free modules for official wigglers!!

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DGTom
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Post by DGTom » Wed Feb 10, 2010 6:42 pm

wetterberg wrote:PURSUE!
Yes please!! I'm going to try the CV in / comparators with something else I've been tinkering with, but, I really wanna see where you go with this meridic.

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meridic
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Post by meridic » Thu Feb 11, 2010 3:28 am

I have not worked to much on this the past couple days, spent awhile trying to figure out how to fool the simulator into giving me realistic results on my idea for adding hysteresis, and tried to simplify my improved input circuitry mostly. Did get the clock output circuitry all sorted out though. Still trying to decide between linear or log for the ADC, leaning towards linear though. I have been somewhat preoccupied with the old PAiA 2720 Lowpass and getting a more useful featureful VCF from it these past couple days.
I think we can really rally behind this idea and get creative as a group;
Well lets see it then, get creative people!
I'm going to try the CV in / comparators with something else I've been tinkering with
As Ian forwarned the circuit does indeed have problems with slowly changing signals especially saw/ramp waves but on any slow continuous waveform. Hysteresis will be a must if you want to use it for slow.

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the bad producer
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Post by the bad producer » Sat Feb 20, 2010 6:29 pm

Hi Meridic, I'd like to design a little PCB to etch for this, is it ready to go as is? or will you be adding more bits to the circuit (like the clock output) I've got the chips on order, so I hope to be able to breadboard this week...

Charlie

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meridic
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Post by meridic » Sat Feb 20, 2010 7:27 pm

It will work as drawn, but I would not build it that way. The circuit has gone through some rework since then and is abit simpler with pulse outs and clock out as well. There are a couple things dealing with the pulse/clock outs that still need to be finalized but other then that the circuit is good to go. It will be awhile before I can run tests, I need to get some fresh 4532s first, but if you want to do the tests I can help you with any troubleshooting that is needed.

I actually ended up changing directions on this and decided to make the sequencer/switch and ADC seperate modules. But those designs have a good ways to go, they are considerably more complex.

If you do want to build the all in one circuit and want to be the guinea pig let me know and I will get you the later schematic and the info about the one potential problem and what you will need to do to fix it if it is a problem.

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meridic
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Post by meridic » Sun Feb 21, 2010 10:04 am

The sun was coming up and I did not feel like sleeping so I got the schematic updated. I scrapped bothering with hysteresis since the added complexity did not seem worth the effort. If you want to run the slow slow stuff through this just run it through a sample and hold first. A few things were not calculated due to lack of sleep, the LEDs current limitting resistor and the RC network on the edge detector. Both are easy to tweak if they do not work right. Added a resolution switch for running audio rate through, but the output is still 0-5V, so if you want +-10 you will need to level shift, I got lazy here, perhaps after sleep I will make the output switch as well. Kept the original input circuit, decided to keep things simple.

If the clock output/binary outputs do not operate correctly it will just take a tweak of the 1k/47pF cap on the input of the XORs. The triggers may not be long enough for some things.

Image

Edit; The binary ABC outputs can also be taken from before the XORs for a gate output instead of a trigger if you would like.

Also the switch inputs do not really want to see anything but +V, once again I got lazy here. But as I mentioned in the previous post there is a fancy rendition in the works, but it is a good ways off still, so something to play with for the time.

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the bad producer
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Post by the bad producer » Tue Feb 23, 2010 8:12 am

Cool, looks like I forgot the 4538 on my order :doh: but it means I can get the other logic chips at the same time (4075 etc)... I think I might breadboard it first, but one thing, what is the circle output thing with a 5V symbol? (I've put a green circle around it) Is it a switched socket? I'd want to build with bananas you see!
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meridic
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Post by meridic » Tue Feb 23, 2010 3:01 pm

--Cool, looks like I forgot the 4538 on my order

Perhaps there is a 4532 on your order?

--Is it a switched socket?

It is.

--I'd want to build with bananas you see!

Then if you would like to keep VC Switch functionality you have a choice to make. Unfortunately there seems to be no simple elegant way to accomplish this functionality in the world of bananas. At least comparativly speaking that is,

Honestly I just threw that in for the hell of it since most people use 1/4" or 1/8", I dumped the VC Switch stuff for my own use, an 8 to 1 switch is just not useful to me. I will keep fun things for banana land in the back of my head and see if I can come up with anything special for those of of us that do not use jacks with a ground/switch.

Also, the ADC can be made linear if you are into that sort of thing, Simplest way is to dump the range switch and replace the top 8 resistors in the chain with diodes. More complex way that retains the resolution switchability is to do a linear resistor cheain like those found in the old korg products.

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