Jim Patchell's Control Voltage Splitter

diablojoy · Posted: Sat Jan 14, 2012 10:29 pm Post subject:

just layed out and built a very rough pnp board today
will see how it goes in testing
may redo it later for euro size
just a little too wide at the moment
haha first test fail put a socket in backward and consequently
also the tl074 , cracked the bastard in half Laughing

diablojoy · Posted: Sun Jan 15, 2012 12:32 am Post subject:

ok working sort of
definitely getting waves blending on both outputs [audio rate]
and they look opposite ok but
i think i have an error in my layout perhaps
cant get any adjustment out of the trim at either end its like its not even there.
+5.9v to -5.9v shows the same at both of the outputs depending on where the pot is
the CV pot does have an effect on the output at least , an LFO into it
is interesting
supply is +15/-15 so tried 301K for the 220k maybe higher needed?
also didnt have 47K for the trimmer so used a 100k multiturn instead

diablojoy · Posted: Sun Jan 15, 2012 2:58 am Post subject:

sorted it ,missed a trace Embarassed

working good now
the trimmer adjustment went well
301K seems good for 15 volt supplies
no time left tonight will try to post something tomorrow

PHOBoS · Posted: Sun Jan 15, 2012 5:49 am Post subject:

Good to hear it's working diablojoy! looking forward to hear your
experiences with it. Razz

About the 220K resistor, it sets the wipe range of the pot. With the range I
choose you should be able to wipe between the 2 inputs. (that is with
10Vpp signals) So, if you can't do a full wipe you would have to decrease
it. And if I remember correctly then if the resister is too small you can
wipe further and end up with just the top or bottom half of one signal
(offset and half the amplitude), but you would have to check it on a scope
to be sure. Could be a feature but I didn't want it. You should also get the
same effect by using a CV with a larger amplitude than the input signals.
(which I might try again so I know for sure what it does).

In the meantime I did another test with a triangle and square wave but
this time the square is shifted 90° compared to the other test. (I like how
it looks at 0V Laughing

) This is actually what I wanted to try, but it's not what
my LFO gave me. So I used a comparator now to convert a triangle into
the square I wanted.

and I also posted the layout I used to build it on perf.

PHOBoS - Wave Wiper graphs2.gif

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asterisk · Joined: Sep 17, 2011 Posts: 17 Location: burlington, VT

this would be a good circuit to make a PCB for.

diablojoy · Posted: Sun Jan 15, 2012 4:19 pm Post subject:

interesting outputs if a higher freq is used into the cv input compared to the normal inputs
nice perfboard layout of yours by the way
the board i drew up has 3 board mounted pots [ i added attenuators on both the normal inputs ] for more variation
so i can try out the bigger cv than input wave form idea
wasnt concentrating on that last night and ran out of time
was thinking an attenuvertor on the cv input might be good
to try out as well
I have to do the layout again anyway need to get it under 44mm wide
dual layer would make it easy to lay out but harder for self etching
A triple or quad panel of these would be good and well worth having
i think
would you consider doing a board run of your final design in the future?
if enough interest develops of course.

emdot_ambient · Joined: Nov 22, 2009 Posts: 667 Location: Frederick, MD

PHOBoS · Posted: Mon Jan 16, 2012 1:38 pm Post subject:

asterisk · Joined: Sep 17, 2011 Posts: 17 Location: burlington, VT

if you get some boards made, count me in for one.

diablojoy · Posted: Mon Jan 16, 2012 5:21 pm Post subject:

it's your design so i figure its up to you
I thought only to do a layout for myself primarily as well
but would happily send you the files if you wanted them , doing a quick layout is not much work for me and gives me a distraction while waiting for my sympleseq parts to come in . if what i do can be shared all the better. this is purely a hobby for me
my thoughts with regards to board design were to bring the board dimensions under 44mm in width for people who work in RU dimensions
with board mounted pots to make building simple and easy.
even better if the jacks were also board mounted
if it can be panelled in a euro format than a lot more people might be interested my 2 cents worth anyway

PHOBoS · Posted: Tue Jan 17, 2012 7:34 am Post subject:

vladosh · Posted: Tue Jan 17, 2012 10:34 am Post subject:

Here's a few scope shots done with PC scope ,but only on one of the outputs just so i be sure it's working right , the last one is triangle with sine i think but that triangle is a bit quiet so this is how it turned out , the odd one is with different slightly detuned vco's

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diablojoy · Posted: Tue Jan 17, 2012 4:06 pm Post subject:

vladosh wrote

diablojoy · Posted: Tue Jan 17, 2012 4:17 pm Post subject:

PHOBos wrote

diablojoy · Posted: Fri Jan 20, 2012 9:36 pm Post subject:

PHOBos see what you think
An extended version

Added attenuvertors to all inputs instead of just attenuators
and another ideal diode cct taken from the outputs [ I had an extra opamp to use up ]
I will prototype this one to make sure it works.
4 x knobs
7 x jacks

see attached schematic

WAVE WIPER EXTENDED.pdf

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PHOBoS · Posted: Sat Jan 21, 2012 8:49 am Post subject:

o wow,.

not really sure what those attenuvertors do. If I ignore the pot on the
non-inverting input (GND it) I see it's an inverting amp with adjustable
gain. with the pot wired to a fixed voltage it would give some offset, but
what does it do now ? (maybe I'll just need to breadboard it)

I am curious how the outputs of the 3rd ideal diode cct look compared
to the inputs. Nice idea to use the spare opamp like this. Maybe you could
add some switches to patch it to different points in the circuit. Or if you use
jacks with switch contacts you could use it as a standalone circuit, but
attached like you drawn now if you don't plug anything in.

asterisk · Joined: Sep 17, 2011 Posts: 17 Location: burlington, VT

the updated circuit looks really great!

what do the additional 2 diode outputs do? is it max/min outputs or something?

attenuverter pots are used to attenuate and/or invert an incoming CV or audio signal. very helpful to have them as part of any circuit so you dont have to do it elsewhere (using attenuators and inverters) before sending signals into the circuit. i think they would be particularly useful in this circuit.

im hoping to breadboard this circuit soon. ill post results if i get it working.

diablojoy · Posted: Sat Jan 21, 2012 6:08 pm Post subject:

diablojoy · Posted: Mon Jan 23, 2012 1:56 am Post subject:

asterisk · Joined: Sep 17, 2011 Posts: 17 Location: burlington, VT

wow, thats great!
itd be nice to have a PCB of this, its starting to get too complicated for a breadboard

diablojoy · Posted: Mon Jan 23, 2012 2:32 pm Post subject:

do you mean a pnp self etch board ?
yes it is getting a little complex for me too
I must admit to a massive dislike of breadboarding though
and havent done any for this
usually i just go straight from the schematic, layout and etch a board
test and then see what needs fixing, then do it all again
not the most efficient methodolgy I know but seems to be the way that suits me best

So I have to build a prototype first and test it
that is what i have started to draw up now.
and there will inevitably be some changes,
there will in the end be some form of board for this
but thats a couple of weeks away at least.

asterisk · Joined: Sep 17, 2011 Posts: 17 Location: burlington, VT

thanks diablo. let us know how your tests go.
id be happy with a self-etch board or a standard PCB run.
anyways, im certainly interested in this circuit.

blue hell · Posted: Tue Jun 16, 2015 4:12 pm Post subject:

This got mentioned in the chat today, and decided to try and make a software version of the WaveWiper. I'm not sure I made exactly the same thing ... but it turned out to be quite a nice wave shaper Cool

The image below is a triangle and a square wave on inputs 1 and 2, with a sine wave on the CV / Break input. Viewing outputs 1 and 2.

Posted Image, might have been reduced in size. Click Image to view fullscreen.

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diablojoy · Posted: Wed Jun 17, 2015 1:02 am Post subject:

nice seems a little more ideal perhaps
I really should relook into this got distracted by numerous other bright shiny things. Embarassed

maybe I could do a proper board now

elmegil · Posted: Wed Jun 17, 2015 7:26 am Post subject: