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Splicer... (new mini-project)
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page 1, 2, 3, 4  Next [all]
Author Splicer... (new mini-project)

J3RK

Edit:




Original Message:

I was thinking about doing a wave splicing sort of thing ala Plan B today. Not sure how Peter did it, so I whipped up my own. (which is probably pretty similar I would imagine)

It's basically two precision half-wave rectifiers (diodes flipped on one) going into a mixer. The rectifiers are inverting, so the phases swap places, and then the mixer (also being inverting) swaps them back to their original phases.

I'm going to whip up a small board for this, and maybe add a feature or three. It's a fairly simple design, made up of common components, so I'm happy to post the schematic once I lay it out as well. Right now I just have it sketched out on paper.

More soon!

w00t


FetidEye

cool! i think i'm ready to build from schematic (if simple enough)

what do you mean by precision rectifiers?


J3RK

FetidEye wrote:
cool! i think i'm ready to build from schematic (if simple enough)

what do you mean by precision rectifiers?


This one should be absolutely no problem for you. One chip, a few resistors, and a few diodes.

By precision, I just me op-amp based rectifiers. (otherwise the waves could come out a little odd...) Nothing terribly special about them. That's just how I've seen them referred to while researching how I might do this.


J3RK

I had a few minutes between a couple of projects tonight, so...

w00t

There's an unused op amp left on the TL074, so this could be used to make an inverted output. Pots could be swapped in on the feedback resistors for gain adjustment as well if desired.




J3RK

Might as well use that last op amp. This is fun!




vurma

This looks quite useful! Keep us updated on that board will ya? ^^


J3RK

Your updated is ready This is fun! Now it's just a matter of seeing if someone wants to stock them. If there's only a small amount of interest, I could do a small run, but I don't have enough time to do a big one right now with all of the shipping etc.

It's ready to place an order though once I have an idea of how to approach it. It will be a very inexpensive board. Could also be fun with a pair of VCAs maybe to have voltage control over the inputs. Not sure what that would look like, but I may try it out.

More as soon as I figure out what to do with it.




microfauna

Is this 12v or 15v? Could you put a Euro power header footprint on?


KNYST

Neat! Yes please w00t
CV input?


vurma

Awesome!

microfauna wrote:
Is this 12v or 15v? Could you put a Euro power header footprint on?


Looking at the PCB, it seems like its already taken care of.


BugBrand

It shouldn't matter 12V/15V -- it is just opamps doing their thing..

CV input? Perhaps simply adding further waves to the input summing nodes - ie. add further resistors like R3 and R4

That extra opamp could, perhaps, be used for CV/Modulation input? Haven't tried, but could it be interesting to have one Mod input going to both input sides, but have one inverted (ie. through that spare opamp) - should be easy to try on your software.


microfauna

vurma wrote:
Awesome!

microfauna wrote:
Is this 12v or 15v? Could you put a Euro power header footprint on?


Looking at the PCB, it seems like its already taken care of.


I see the header shape, but not the solder points.


KNYST

I have a M39. I'd say the VC input on it is essential. Morphing, fading between the input waves...
When nothing is plugged in into the VC input, one can use the pot to sweep between the two input signals.

For anyone interested, read more here: http://www.modulargrid.net/e/plan-b-model-39


catchpenny

does this work with CV signals?


BugBrand

CV/DC - yes (well, presumably..)

Knyst - I think.. that my suggestion for the final 1/4 opamp with one CV input going inverted & non-inverted could well do that cross-fading. It makes sense in my head, at least.. Oh - or maybe you DON't want to invert the CV. Hmm. Simulation needed!


KNYST

^
ah, yes, thanks.

Will be following this with interest.


BugBrand

AHHH!

Did a quick sim (I'm not very good with such things actually)

You just need to add the CV (non-inverted) to BOTH nodes
but then ALSO into the summing node after the half-wave-rectifiers.

Oooh!


BugBrand



OK - wow, so that's kind of like a cross-fader...

Here I have a 10Hz and 50Hz sine going in
0.1Hz sine for modulation.


KNYST

applause


vurma

BugBrand wrote:
AHHH!

Did a quick sim (I'm not very good with such things actually)

You just need to add the CV (non-inverted) to BOTH nodes
but then ALSO into the summing node after the half-wave-rectifiers.

Oooh!


Haha! Sounds like some good hacking is going on over there. What software are you using for the simulation?


BugBrand

LTSpice - free!
http://www.linear.com/designtools/software/

Only been learning it quite recently..


BugBrand

Wow (again)
The idea works in the nord g2 demo software too!


J3RK

microfauna wrote:
Is this 12v or 15v? Could you put a Euro power header footprint on?


It will run on either with no changes. Also, yes, a Euro header would be quite easy to add, and I'll definitely add it.


J3RK

BugBrand wrote:
AHHH!

Did a quick sim (I'm not very good with such things actually)

You just need to add the CV (non-inverted) to BOTH nodes
but then ALSO into the summing node after the half-wave-rectifiers.

Oooh!


Nice! That's very cool! I was going to suggest that I add a VCA in front of each input, (which could still happen,) but your way is much smaller! Thanks for looking at this. 8_) thumbs up applause


oberkorn

Quote:
If there's only a small amount of interest

interested! I'm in for two

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