Dielectric Absorption

Where we discuss new analog design ideas for Pro Audio and modern spins on vintage ones.
terkio
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Re: Dielectric Absorption

Post by terkio » Wed Sep 04, 2019 6:31 pm

A lumped model.
Does this model explain the clicking issue about microphone preamps phantom power isolation capacitors ?
Can on measure the characteristics of this capacitor and resistor array ?

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mediatechnology
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Re: Dielectric Absorption

Post by mediatechnology » Fri Sep 11, 2020 6:58 pm

901 days later, after being discharged into a dead short, this cap still has 0.37V on it.
You would think that by now I would have gotten bored with this and just thrown it back into the bin, but no... :lol:
https://ka-electronics.com

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JR.
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Re: Dielectric Absorption

Post by JR. » Sat Sep 12, 2020 10:04 am

Coincidentally I was just arm wrestling a puke on Geekslutz about audibility of DA..... :lol:

JR
It's nice to be nice.

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mediatechnology
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Re: Dielectric Absorption

Post by mediatechnology » Sat Sep 12, 2020 10:28 am

The one place where I think I might be able to hear it is the timing capacitor in an RMS or averaging detector sidechain.

In the Pico we used a tantalum timing cap for its low leakage but they also have a high DA. (I had that wrong - you corrected me.) https://proaudiodesignforum.com/forum/p ... =20#p10150

Compressing inputs which have a gentle envelope using a detector capacitor having a high DA might cause gain changes to occur in the wrong direction with near steady-state (sustained) inputs.

If I were ever to do a super-duper compressor I would consider a film cap for the timing capacitor role. https://proaudiodesignforum.com/forum/p ... =20#p10149

A big honkin' 22 µF film just looks more impressive than a tiny 22 µF bead tantalum and with the cost of tantalum being what it is they might be about the same price.

DA in a mic preamp input coupling capacitor is more of a nuisance than anything else.

Good luck over at Geekslutz: You're arguing with some of the smartest people in the room if not all of planet Earth. :lol:
I stopped going there...
https://ka-electronics.com

Plandemic Series: "Pland3mic - Indoctornation" https://proaudiodesignforum.com/content ... nation.mp4
Plandemic Series: "Plandemic - Doctors In Black" https://proaudiodesignforum.com/content/Plandemic.mp4

CDC: "For 6% of the deaths, COVID-19 was the only cause mentioned. For deaths with conditions or causes in addition to COVID-19, on average, there were 2.6 additional conditions or causes per death." https://www.cdc.gov/nchs/nvss/vsrr/covi ... /index.htm

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JR.
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Re: Dielectric Absorption

Post by JR. » Sat Sep 12, 2020 10:46 am

mediatechnology wrote:
Sat Sep 12, 2020 10:28 am
The one place where I think I might be able to hear it is the timing capacitor in an RMS or averaging detector sidechain.
This is an old story of mine but about the only time I ever used a high DA cap on purpose was in the side chain of the CX decoder kit I did back in the 80s. Popular electronics offered me a cover article in the Christmas issue, and CBS offered me a free CX license. ;)

Besides discovering a timing error in the side chain of proforma decoder circuit design provided to licensees by CBS (that I corrected). I also noticed that the professional encoder designed by Urie used a tantalum cap in the encoder side chain. In my pursuit of accuracy and best possible tracking, I used a tantalum cap in my decoder side chain too.

I advised CBS about the time constant error but never heard back from them. Quite by accident at the AES show in NY just weeks before my kit article hit the newsstands, while talking to engineers in the Urie booth, they said "so you are that guy." :lol: Since two other licensees had copied the mistake verbatim and already built tens of thousands of decoders, CBS decided to change the encoder time constants to agree with the mistake, :roll: making me the odd man out for doing it right. Luckily I was able to rush changes to my article before it went to press, but it was close (screw CBS they deserved to crash and burn).

JR
In the Pico we used a tantalum timing cap for its low leakage but they also have a high DA. (I had that wrong - you corrected me.) https://proaudiodesignforum.com/forum/p ... =20#p10150

Compressing inputs which have a gentle envelope using a detector capacitor having a high DA might cause gain changes to occur in the wrong direction with near steady-state (sustained) inputs.

If I were ever to do a super-duper compressor I would consider a film cap for the timing capacitor role. https://proaudiodesignforum.com/forum/p ... =20#p10149

A big honkin' 22 µF film just looks more impressive than a tiny 22 µF bead tantalum and with the cost of tantalum being what it is they might be about the same price.

DA in a mic preamp input coupling capacitor is more of a nuisance than anything else.

Good luck over at Geekslutz: You're arguing with some of the smartest people in the room if not all of planet Earth. :lol:
I stopped going there...
It's nice to be nice.

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