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capicoso
Joined: Nov 19, 2012 Posts: 128 Location: Argentina
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Posted: Wed Jan 09, 2013 1:14 pm Post subject:
Question about vco capacitor Subject description: mica |
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Hello. I'm building the vco. And here i have problems finding the silver mica capacitor 1%. So far i found silver mica 270pf BUT +-10% not 1%. NP0 ceramics 220 or 270, or polypropylene. The silver mica one is still the best even with 10% tolerance?
thanks |
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isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
Audio files: 18
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capicoso
Joined: Nov 19, 2012 Posts: 128 Location: Argentina
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Posted: Sat Jan 12, 2013 5:49 pm Post subject:
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Hello, thanks for your time.
Yes i can, but at my local stores i couldn't find either. So my options are 10% mica, np0 or polypropylene.
I'm going to use LF442. I couldn't find 2137 here and someone that built like 3 or 4 vco told me that CA3240 is cheaper and it works the same. Or Lf442 also works. |
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isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
Audio files: 18
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Posted: Sun Jan 13, 2013 12:17 am Post subject:
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Really?
I have some 442's, I wander what will be the deference using 442's or tl072 like Yves recomands.
EDIT:
Yves, what will be preferred instead OPA2137, TL072 or LF442?
Cheers. _________________ http://www.myspace.com/mgmtrance |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Sun Jan 13, 2013 10:27 am Post subject:
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The question of film vs NP0/C0G caps comes up pretty regularly, and I have never seen any convincing reason why film would be preferrable. I still use them because I have a stock, but the long term plan is to get more stock of the C0G's.... |
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capicoso
Joined: Nov 19, 2012 Posts: 128 Location: Argentina
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Posted: Sun Jan 13, 2013 11:00 am Post subject:
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elmegil wrote: | The question of film vs NP0/C0G caps comes up pretty regularly, and I have never seen any convincing reason why film would be preferrable. I still use them because I have a stock, but the long term plan is to get more stock of the C0G's.... |
Yeah, i searched and that's why i ask about the NP0 caps ( i didn't know about their existence)I guess i'm going to use NP0. They're way cheaper and in the datasheets they look goood
but my main question now is if it has to be 1% |
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yusynth
Joined: Nov 24, 2005 Posts: 1314 Location: France
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Posted: Sun Jan 13, 2013 12:02 pm Post subject:
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Any precision dual AOP will do. The important is that it has a low bias.
Concerning the cap, the important is the temperature coefficient which must be kept low (500ppm maximum), in general silver mica and styroflex are offering that. The 1% tolerance is not really important unless you want to built plenty of VCOs and you want them to behave the same. _________________ Yves |
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capicoso
Joined: Nov 19, 2012 Posts: 128 Location: Argentina
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Posted: Sun Jan 13, 2013 4:53 pm Post subject:
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Well my idea would be having various VCOs. If i use NP0 then i think i'll have to match them to 1%. When you say they'll behave different, you mean they'll be tuned differently? Or...?
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yusynth
Joined: Nov 24, 2005 Posts: 1314 Location: France
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Posted: Mon Jan 14, 2013 12:06 am Post subject:
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Yes, "tune differently" _________________ Yves |
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