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Post by mathieuteissonniere on May 27, 2020 20:04:09 GMT
Hi,
this is my first message on the forum, though I bought my starter rack last year and just made another order for new modules. I'm no electronician and have a little knowledge (owner of an OMSynth). I have a question :
I'm trying to build a very slow triangle lfo. I've been trying different things from Schmitt Trigger (big caps) to Op amp etc. Everything could be fine but I always get a very small voltage amplitude (no 0 to 5 v) unless I use bipolar -12v to 12v (but I want it the "AEM" way). Is there any way to get more amplitude with a triangle wave from a 40106 under 5v (which is 1/3 to 2/3 the VCC so about 2.2 to 3v) ? Buffering LFO triangle doesn't work (unless I miss something).
I know there is another option. I can use a very slow AREG retriggering (self-oscilating) as with the 2ENV. This is fine but still a bit "fast" for me so I don't think it's a good option (maybe it is but I can't get tips to make a slower AREG than the 2ENV does).
Hoping you can help me.
Mathieu |
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Post by MikMo on May 27, 2020 20:14:29 GMT
One option would be to change a capacitor on one of the AE LFO's to a larger capacitor.
Would probably need to solder SMD though...
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Post by mathieuteissonniere on May 27, 2020 20:37:24 GMT
Of course ! I didn't think about it. The only thing is, as you say, soldering through/beside/next to smd is always a bit tricky and I ordered the DIY kit and the Braedboard, so I'd rather use these. The other thing is, I don't know which tech Robert used on the LFO. Are larger caps are always an option ?
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Post by MikMo on May 27, 2020 20:53:37 GMT
I don't know for sure but timing in LFO's are often decided by an RC network, a capacitor charging or discharging through a resistor. Changing the capacitor increases the RC time. I don't now how the AE LFO's are constructed, but my guess is there is a timing cap in there  |
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namke
wonkystuff
electronics and sound, what's not to like?!
Posts: 654
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Post by namke on May 27, 2020 22:31:40 GMT
If you make a ‘classic’ Inverter based oscillator, e.g. with a 40106, you could also amplify and buffer that triangle output by using a 4049 of 4069 as an inverting amplifier. This would (with correct choice of resistors) amplify your LFO up to 0-5v.
I expect that a google search would turn up something or other…
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Post by admin on May 27, 2020 22:46:04 GMT
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Post by mathieuteissonniere on May 28, 2020 6:19:52 GMT
If you make a ‘classic’ Inverter based oscillator, e.g. with a 40106, you could also amplify and buffer that triangle output by using a 4049 of 4069 as an inverting amplifier. This would (with correct choice of resistors) amplify your LFO up to 0-5v. I expect that a google search would turn up something or other… Haven't tried that yet. I buffered it with a TL082 liying around. It amplified the global signal but lowered the amplitude between low and high voltage of the triangle. |
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Lugia
Wiki Editors
Ridiculously busy...ish.
Posts: 556 
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Post by Lugia on May 28, 2020 17:20:27 GMT
Of course, you could always try an outside solution. For example, right next to where I'm typing this, I've got a Wavetek 142, a function generator with CV over frequency (albeit not scaled the way we're used to, but that can be messed with). Since this thing is capable of running down as low as .0001 Hz, I can get periods of over 160 MINUTES out of it.
Now, it's important to note that this sort of gear can and WILL produce signal levels far beyond what the AE can deal with (ie: 30V p-2-p), so it's essential that you first check your function generator's output levels with a multimeter to make sure you're within the 0-5V window (it also has an offset so that you can center the waveform on a voltage point in that range, as desired) and then DO use something like the 4I/O or (my choice) a Soundmachines Nanobridge to ensure that nothing pops up by accident.
Plus, test gear looks BADASS...gives you that touch of bigtime academic studio decor in addition to some really interesting functionalities. Check some of Hainbach's videos (https://www.youtube.com/channel/UCeovElJP0n0i8ADaPsRSd8g) and see...
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Post by sycophante on May 28, 2020 17:51:17 GMT
Couldn't a GRAINS be programmed to do this ? This would be cool!
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Post by mathieuteissonniere on May 31, 2020 9:11:56 GMT
Thanks everybody,
I've found out an alternative solution. Arduino and 4 lines of code to ramp up and down from 0 to 5v, then ripple the PWM with an RC filter, pot for time range and LED control. I'll send the schematics soon and it will fit in my DIY module. Sound example here of the superslowlfo. |
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Post by slowscape on Jun 1, 2020 20:51:17 GMT
hehe I was just going to suggest arduino. Those things are darn handy (and simple) for stuff like this!
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Post by korporation on Jun 21, 2020 7:34:04 GMT
Hexinverter Galalean Moons is prolly the slowest LFO I've used. 10 minute rise and 10 minute fall times. I think Qu-bit Contour does 20 minute rise/fall.
Overkill sure, but only drone is real. And not that this adds anything useful to the thread hahahah. I just like slow LFOs, too.
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Post by mathieuteissonniere on Jun 21, 2020 9:56:50 GMT
Hi,
still working on it but the proto si now operational. It will feature 3 independant LFO's with at least CV in, internal CV (for complex operation from an lfo to the others), retrig, freeze and of course CV out.
I'm working on a possibility to calibrate the max time with a shift button for each LFO.
I'll tell you very soon. Cheapo arduinon nano, a few resistors and caps and voilà !
Mathieu
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Post by Daniel Linger on Jun 28, 2020 14:12:31 GMT
Count me in!
I've recently dipped my toes into the waters of Arduinos and project building, and a really slow LFO is something I really could use a lot.
Thanks for doing this mathieuteissonniere!
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Post by MikMo on Jun 28, 2020 18:39:31 GMT
Funny :-) i'm also working on a (slow) Arduino based LFO.
For now i have it working with 5 waveforms (sine,triangle, square, ramp up, ramp down). Square wave has variable PW.
I have two ranges covering 5Hz to 2 minutes pr. cycle.
Still a few rough spots in the software.
Next up is trying to get CV in for freq. and PWM.
Mikael / MikMo
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Post by rodney on Jul 2, 2020 2:40:53 GMT
So many MCUs have WiFi build in, you could also include bitcoin prices, although they might not always be so low-frequency...
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