[sdiy] VCF caps in modern synths

Mike Bryant mbryant at futurehorizons.com
Mon Jan 11 13:04:46 CET 2021


OK.  Maybe back then they didn't have what are called automotive class lead frames but were actually developed for phones first.



-----Original Message-----
From: Roman Sowa [mailto:modular at go2.pl] 
Sent: 11 January 2021 12:00
To: Mike Bryant; synth-diy at synth-diy.org
Subject: Re: [sdiy] VCF caps in modern synths

That was maybe 8-10 years ago.

Roman

W dniu 2021-01-11 o 12:20, Mike Bryant pisze:
> Worrying with Samsung.  Is that some time ago ?   I never use Murata for a different reason but all should be quality brands.
>
> Yes it was about 1998 that the problem got fixed.   The Nokia 'banana' phone in 1996 was the first to start getting on top of the problem.
>
> Yes I don't understand why there are 1nF and less X7Rs either.  At that size the NP0s are so cheap and same size you just use them.
>
> Mike
>
> -----Original Message-----
> From: Roman Sowa [mailto:modular at go2.pl]
> Sent: 11 January 2021 10:41
> To: Mike Bryant; synth-diy at synth-diy.org
> Subject: Re: [sdiy] VCF caps in modern synths
>
>
>
> W dniu 2021-01-08 o 17:31, Mike Bryant pisze:
>> No 1mV is large and worrying.  What brand was it ?   For 1-10uF I only use Samsung
> I can't be sure, I took it from my P&P spit-it-out bin. Might have been Murata or AVX.
> I don't use Samsung since the time I saw them cracking in pieces while soldering. Only few of them, but never experienced that with other brands. Again this may be more my personal trauma with Samsung rather than scientificaly proved lack of quality.
>> If you recall the first mobile phones had lots of 'handling noise' as they were stuffed full of microphonic components, not just SMD capacitors but even microphonic connectors, as well as poor microphones.  It was a good decade before they were properly quiet.
> Actually I can't recall any handlig noise, but I was using cellphones only since 1998.
>
>> Agreed that sounds like dielectric effect.  Only expect to see that sort of percentage with electrolytics.  Definitely well out of spec - 2.5% is the worse spec I've seen even on crap Chinese brands.
>>
>> Surprised you even had a 1nF X7R to hand - at that size the price difference is minimal.
> Whatever the reason was it got into my hands, was not the price. It was probably sitting 10 years in my drawer. Maybe at the time of purchase the store didn't have C0G of that value so I got X7R for a project that wasn't so immune to dielectric type.
> For some reason today you can still buy sub-pF capacitors in X7R, as well as 0.1uF electrolytic caps.
>
> Roman
>






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