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efabric
Joined: Jan 05, 2012 Posts: 19 Location: Caen, France
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Posted: Mon Mar 26, 2012 7:30 am Post subject:
Simple Low pass resonant filter for your lunetta |
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Hello,
I found a long time ago this schematic on the squarewaveparade website :
http://thesquarewaveparade.com/images/srlpf.jpg
It's a 1 opamp low pass filter.
I'm not sure, but I think therr's a little mistake in the In and Out jacks ground. Don't the input and output must be decoupled with capacitors ?
The virtual ground in the power supply (4,5v) is directly linked to the ground output and input.
I think it's false no ?
Thank you. _________________ My Scoopit DIY Synths and Schematics curation Last edited by efabric on Tue Mar 27, 2012 12:33 am; edited 1 time in total |
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Psyingo
Joined: Jun 11, 2009 Posts: 248 Location: Canada
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Posted: Mon Mar 26, 2012 9:17 am Post subject:
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Yep, that's a classic sallen-key filter. Replace the dual gang pot with two vatrols for simple voltage control. That's my favorite filter topology. |
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richardc64
Joined: Jun 01, 2006 Posts: 679 Location: NYC
Audio files: 26
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Posted: Mon Mar 26, 2012 10:30 am Post subject:
Re: Simple Low pass resonant filter for your lunetta |
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efabric wrote: | The virtual ground in the power supply (4,5v) is diretly linked to the ground output and input. |
It's fine, as long as the 9V that powers it isn't used to also power something that expects -9V to be ground -- in other words, single-supply. _________________ Revenge is a dish best served with a fork... to the eye |
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efabric
Joined: Jan 05, 2012 Posts: 19 Location: Caen, France
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Posted: Tue Mar 27, 2012 1:05 am Post subject:
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It's a little bit strange...
I'm planning to build my modular lunetta with various units : 5v CMOS and ?V opamp based analog circuits.
What is the good way for everything to work together ?
I have a nice working radial transformer regulated 10V power supply in my bench, and 5V regulators in my spare parts.
Do you thik I can use this 0V, +10V and +5V to power up my opamps ?
Can I use the same +5V to power the CMOS modules and the virtual ground of the opamps ? Is there a risk of parasitic digital noise in the analog path ?
Can you show me a diagram with the interconnections and the decoupling stages ? _________________ My Scoopit DIY Synths and Schematics curation |
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