[sdiy] VCF caps in modern synths

Mike Bryant mbryant at futurehorizons.com
Thu Jan 7 21:47:34 CET 2021


> but for a specialised application the cost difference between the two types is minimal.

10k+ 10nF 0805 +-5% NP0 is 3.2c.
10k+ 10nF 0805 +-10% X7R is 0.8c.

With that difference, any commercial product designer will check very carefully do they really need a 4 times more expensive NP0 and will have to justify their use in each and every location.  Of course many filters will need them because of the better accuracy, but many other locations probably don't.




-----Original Message-----
From: Neil Johnson [mailto:neil.johnson71 at gmail.com] 
Sent: 07 January 2021 20:30
To: Mike Bryant
Cc: ColinMuirDorward; Vladimir Pantelic; *SYNTH DIY
Subject: Re: [sdiy] VCF caps in modern synths

Hi,

Mike Bryant wrote:
> Manufacture of polycarb capacitors stopped in the late 1990s so I really doubt if anyone is using them now.  I assume it was an old document in dire need of updating to modern capacitor technology.

"Old" is a relative term.  It was written last year, and I'm sure there are improvements to be made.  Pretty much all SMT capacitor choice for filters is C0G/NP0 now, sure X7R has improved over the years, but for a specialised application the cost difference between the two types is minimal.

I'll be sure to remove polycarbonate from the list in the next rev.

Neil





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