[sdiy] Query about best cap type for '2164 stability network

Guy McCusker guy.mccusker at gmail.com
Sun May 6 19:16:12 CEST 2018


Thanks Richie.

You've given several reasons that C0Gs are good in general, and that's
why I tend to go for C0G for small value caps if I don't have a good
reason not to. But in the spirit of trying to learn about this stuff
properly, I wondered if there are any reasons particular to the 2164
application that would call for C0G over something else.

It doesn't seem to me that the capacitance change with voltage or
temperature are essential in this application. The high frequency
performance may be. Is it?

I realise that from an actual building standpoint this is a somewhat
academic question - we can just use C0G and stop worrying - but I like
worrying / learning.

On Sat, May 5, 2018 at 9:41 AM, Richie Burnett
<rburnett at richieburnett.co.uk> wrote:
> Low capacitance change with voltage and with temperature, low microphony, low loss at high frequency. C0G is the best you can get in small C values, in every respect except maybe size and cost. So no reason not to use it here for DIY unless you're counting every last penny or need to fit hundreds of them into a small space. But just for small cap sizes like hundreds of pF.
>
> -Richie,
>
> Sent from my Xperia SP on O2
>
> ---- Guy McCusker wrote ----
>
>>What is the advantage of C0G in this application? Voltage derating and
>>temperature coefficient don't seem critical. Could an X7R cap do bad /
>>not as good things here?
>>
>>David is right that most of the 560pf ceramics at the usual
>>distributors are C0G, but some are not, X7R being the next most
>>popular. Tayda have some Z5U it seems.
>>
>>
>>
>>On Fri, May 4, 2018 at 9:32 PM, David G Dixon <dixon at mail.ubc.ca> wrote:
>>> Yes, that's what I meant to say as well (I believe that virtually all 560pF
>>> MLCC caps are NP0/C0G anyway).
>>>
>>>> -----Original Message-----
>>>> From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On
>>>> Behalf Of rburnett at richieburnett.co.uk
>>>> Sent: Friday, May 04, 2018 3:05 AM
>>>> To: *SYNTH DIY
>>>> Subject: Re: [sdiy] Query about best cap type for '2164
>>>> stability network
>>>>
>>>> NP0 / C0G ceramic
>>>>
>>>>
>>>> On 2018-05-04 10:32, Tom Wiltshire wrote:
>>>> > Hi All,
>>>> >
>>>> > What type of capacitor would be most suitable for the 500R/560pF
>>>> > stability network on the input of the 2164 VCA? (In
>>>> practice I mostly
>>>> > use 560R/470pF - easier values to get).
>>>> >
>>>> > It's not directly in the audio path, so film caps seems
>>>> like overkill.
>>>> > Instead it's to take interference to ground, so it feels to me like
>>>> > ceramic is appropriate.
>>>> > Is that right, or would I be better off with something
>>>> else? I realise
>>>> > any improvement is unlikely to be audible, but I'm looking for
>>>> > guidance on "best practice".
>>>> >
>>>> > Thanks,
>>>> > Tom
>>>> >
>>>> > ==================
>>>> >        Electric Druid
>>>> > Synth & Stompbox DIY
>>>> > ==================
>>>> >
>>>> >
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