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kkissinger
Joined: Mar 28, 2006 Posts: 1354 Location: Kansas City, Mo USA
Audio files: 42
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Posted: Fri Apr 29, 2011 5:33 am Post subject:
Re: Just built two VCLFOs |
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kkissinger wrote: | Also, on the LOW frequency range, I get a large offset voltage. Anyway, once I get non-polarized in place I hope this takes care of the symptoms. |
Just to follow up: I reviewed the schematic and found that I had missed that the VCLFO has separate offset adjustments for the low and high ranges. Thus, the offset problem was nothing more than a trim adjustment.
Thus, the only outstanding issue is the sync issue -- not a huge issue and could almost be a "feature". _________________ -- Kevin
http://kevinkissinger.com |
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kupfer_m
Joined: Oct 14, 2010 Posts: 48 Location: Belgium
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Posted: Mon May 02, 2011 8:25 am Post subject:
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yusynth wrote: | LektroiD wrote: | The spikes are really obvious through a VCF or VCA. Any way to tame them? |
Try and change the tantalum cap until you minimize the glitch. |
I have the same problem with my VC-LFO2. But I also get spikes on the x1 setting. Will try with some other capacitors. |
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LektroiD
Joined: Aug 23, 2008 Posts: 1018 Location: Scottish Borders
Audio files: 2
G2 patch files: 2
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Posted: Wed Jun 29, 2011 4:44 am Post subject:
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kupfer_m wrote: | yusynth wrote: | LektroiD wrote: | The spikes are really obvious through a VCF or VCA. Any way to tame them? |
Try and change the tantalum cap until you minimize the glitch. |
I have the same problem with my VC-LFO2. But I also get spikes on the x1 setting. Will try with some other capacitors. |
did the other capacitors work?
Just a thought, this thread could maybe merge with the other VCLFO one, since it's the same issue _________________ LektroiD |
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kupfer_m
Joined: Oct 14, 2010 Posts: 48 Location: Belgium
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Posted: Wed Jun 29, 2011 9:02 am Post subject:
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No, still those nasty clicks...
Tried a MAXIM 7555 (more expensive) but still the same.
One day I will find it |
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vinnui
Joined: Jun 12, 2009 Posts: 19 Location: Hungary
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Posted: Mon Jul 04, 2011 9:07 am Post subject:
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I'm building 3 VC-LFO-2s, and today i've checked the waveforms of my first LFO build. The spikes were here. I've found, that i've used a NE555, which i've replaced with a ICM7555CN (I think it's a Philips part). After a complete recalibration procedure, the spikes are gone. |
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adambee7
Joined: Apr 04, 2009 Posts: 420 Location: united kingdom
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Posted: Mon Jul 04, 2011 1:57 pm Post subject:
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ive noticed on the schematics that there is no current limiting resistor going to the power pin of the 555. Would this be worth adding. usually its 100ohms. |
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yusynth
Joined: Nov 24, 2005 Posts: 1314 Location: France
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Posted: Tue Jul 05, 2011 4:05 am Post subject:
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adambee7 wrote: | ive noticed on the schematics that there is no current limiting resistor going to the power pin of the 555. Would this be worth adding. usually its 100ohms. |
This is only valid if one uses the non CMOS version of the 555 ! Here we are using a CMOS 555 and this resistor is of no use. _________________ Yves |
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adambee7
Joined: Apr 04, 2009 Posts: 420 Location: united kingdom
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Posted: Tue Jul 05, 2011 10:10 am Post subject:
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thanks yves . now to find some phillips 555. |
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gibrancurtiss
Joined: Mar 16, 2016 Posts: 22 Location: brazil
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Posted: Sat Apr 08, 2017 6:57 pm Post subject:
changed C5 |
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Changed the C5 from 47pf with other values 470pf and 1K.
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