Atari Punk LFO?

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ex_dead_teenager
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Atari Punk LFO?

Post by ex_dead_teenager » Wed Jul 08, 2009 1:59 am

Anyone ever made anything like this? I've been wanting to get into SDIY for a while and the thought of an external modulation box for my synth is really appealing to me (more so than a normal APC) and I think I'd use it more than another noisy box.

Anyone on here got suggestions on where or how to start something like this?

cheers.

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DGTom
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Post by DGTom » Wed Jul 08, 2009 2:47 am

an APC with bigger timing capacitors will generate very slow oscillations, but, squarewaves, not much fun for CVing stuff - very cool for triggering (EGs, LFO resets etc.) stuff tho.

You could build 2, feed them into a basic DAC & slew processor built around a dual op-amp & you would have a superbad LFO that'd run off a 9V :goo:

Sounds more complex than it is trust me. I've got a 2 input R2R on my breadboard at the moment & its lots of fun driving an oscillator. Being so simple you get quite predictable results.

There are even easier ways to oscillate than the APC, but, it would be kind of a cool place to start.

Would even work just to run a low freq. APC thru a slew processor which is basically an op-amp, a pot, a capcitor & one or two resistors.

R2R;

http://deathlehem.com/php/viewtopic.php?f=6&t=30

Slew;

http://deathlehem.com/php/viewtopic.php?f=6&t=193


This;

http://electro-music.com/forum/forum-160.html

is another good place to start digging into very simple, very effective ccts. Fair warning; its addictive!

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Luka
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Post by Luka » Wed Jul 08, 2009 2:53 am

building a proper lfo is pretty easy
check out the cgs utility lfo

Image

it might look pretty complex but there are 2 of the same circuits so it isnt too bad. each triangle symbol there is an opamp so you can do a whole thing with 1 quad opamp like a tl074

just go grab some perfboard and the components and there you go
good startup project

normally i would suggest trying to build small things like the APC or other noise makers but since you have a modular anyway may as well just try your luck out on simple things that will work well in your machine

btw you can buy the pcb for this project from the cgs site
that might make it even easier :)

http://www.cgs.synth.net/modules/cgs58_lfo.html

and you can get parts kits & pcbs from bridechamber and elby designs

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ex_dead_teenager
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Post by ex_dead_teenager » Wed Jul 08, 2009 4:34 am

hmmmn... wheels are turning...

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DGTom
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Post by DGTom » Wed Jul 08, 2009 5:23 am

Psyco LFO would be easier / quicker than the Utility LFO for a starter project.

Depends what you've made before. But in terms of parts count & straightforwardness, a pair of 40106 RC oscillators & an R2R w/ glide is like a dozen resistors, 3 caps, 2 ICs & a bunch of wire... LEDs if you wanna get fancy & it will be something differant to a normal LFO you've already got.

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Luka
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Post by Luka » Wed Jul 08, 2009 5:35 am

psycho lfo was my first module :)

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