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kaputtpanzer
Joined: Nov 02, 2009 Posts: 139 Location: Cologne
Audio files: 15
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Grumble
Joined: Nov 23, 2015 Posts: 1294 Location: Netherlands
Audio files: 30
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Posted: Mon Jan 28, 2019 1:16 pm Post subject:
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the output of the triangle waveform is coupled by a capacitor, which removes dc hence you end up with an ac voltage.
measure before the 10uF cap and you measure dc. _________________ my synth |
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
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Posted: Mon Jan 28, 2019 5:09 pm Post subject:
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I've deleted some spirals here. _________________ Jan
also .. could someone please turn down the thermostat a bit.
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MapacheRaper
Joined: Feb 15, 2018 Posts: 166 Location: Spain
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Posted: Tue Jan 29, 2019 4:03 pm Post subject:
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The neutron should be capable of accepting anything from+10 to -10 without blowing up, as any eurorack gear.
Probably the neutron fail is not related to your LFO, it´s just a coincidence... It´s a pity, but Beh will proabably give you a new one. Just dont comment them about your LFO... |
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kaputtpanzer
Joined: Nov 02, 2009 Posts: 139 Location: Cologne
Audio files: 15
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Posted: Thu Jan 31, 2019 3:50 pm Post subject:
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Grumble wrote: | the output of the triangle waveform is coupled by a capacitor, which removes dc hence you end up with an ac voltage.
measure before the 10uF cap and you measure dc. |
Thanks for your reply. Yes I know that, I put the capacitor to the output to get rid of the dc offset voltage But it seems I have a lack of knowledge regarding measuring ac voltages. I just was confused why there is a negative voltage, when I use 0V as reference point with a single supply lfo. I just didn't understand why there is a lower value then 0V when measuring in dc mode. Last edited by kaputtpanzer on Fri Feb 01, 2019 4:38 am; edited 2 times in total |
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kaputtpanzer
Joined: Nov 02, 2009 Posts: 139 Location: Cologne
Audio files: 15
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Posted: Thu Jan 31, 2019 3:58 pm Post subject:
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MapacheRaper wrote: | The neutron should be capable of accepting anything from+10 to -10 without blowing up, as any eurorack gear.
Probably the neutron fail is not related to your LFO, it´s just a coincidence... It´s a pity, but Beh will proabably give you a new one. Just dont comment them about your LFO... |
Yes, the neutron was acting a bit strange after the last firmware update. I don't think it has anything to do with my "low voltage lfo" it is weird, because the VCF stopped working with the envelopes and even with the VCA bypassed, but it was still working with the internal LFO Otherwise no sound from the VCF, nothing. It felt a little bit like a weird software issue or that i somehow disabled the VCF with a secret keypress |
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Hashtag Octothorpe
Joined: Jun 11, 2017 Posts: 57 Location: Grand Rapids MI
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Posted: Fri Feb 01, 2019 1:54 pm Post subject:
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kaputtpanzer wrote: | Grumble wrote: | the output of the triangle waveform is coupled by a capacitor, which removes dc hence you end up with an ac voltage.
measure before the 10uF cap and you measure dc. |
Thanks for your reply. Yes I know that, I put the capacitor to the output to get rid of the dc offset voltage But it seems I have a lack of knowledge regarding measuring ac voltages. I just was confused why there is a negative voltage, when I use 0V as reference point with a single supply lfo. I just didn't understand why there is a lower value then 0V when measuring in dc mode. |
Without the capacitor in there to "get rid of the DC offset voltage" the average DC voltage coming out of a 5V peak-to-peak oscillator would be +2.5V, right? Even though it's oscillating and would seem to be not DC....... but there is an offset.
So when you toss a capacitor in the signal stream, you're taking that "offset" of +2.5V and making it 0V, so anything below that is negative.
The DC-blocking capacitor is "sucking" current back from the output, and that's where the negative voltage is coming from. If you take the 10uF cap and the 47K resistor away from the output of the final op amp, you should get the values you're looking for. |
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kaputtpanzer
Joined: Nov 02, 2009 Posts: 139 Location: Cologne
Audio files: 15
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Posted: Thu Feb 07, 2019 6:48 am Post subject:
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Oh man, haha I finally got it well that was actually so obvious, but it totally confused me. Embarrassing . Thank you very much!
Hashtag Octothorpe wrote: | kaputtpanzer wrote: | Grumble wrote: | the output of the triangle waveform is coupled by a capacitor, which removes dc hence you end up with an ac voltage.
measure before the 10uF cap and you measure dc. |
Thanks for your reply. Yes I know that, I put the capacitor to the output to get rid of the dc offset voltage But it seems I have a lack of knowledge regarding measuring ac voltages. I just was confused why there is a negative voltage, when I use 0V as reference point with a single supply lfo. I just didn't understand why there is a lower value then 0V when measuring in dc mode. |
Without the capacitor in there to "get rid of the DC offset voltage" the average DC voltage coming out of a 5V peak-to-peak oscillator would be +2.5V, right? Even though it's oscillating and would seem to be not DC....... but there is an offset.
So when you toss a capacitor in the signal stream, you're taking that "offset" of +2.5V and making it 0V, so anything below that is negative.
The DC-blocking capacitor is "sucking" current back from the output, and that's where the negative voltage is coming from. If you take the 10uF cap and the 47K resistor away from the output of the final op amp, you should get the values you're looking for. |
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