Dielectric Absorption

Where we discuss new analog design ideas for Pro Audio and modern spins on vintage ones.
KMN
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Joined: Sat Jan 20, 2018 3:49 pm

Re: Dielectric Absorption

Post by KMN » Fri Jul 20, 2018 9:47 pm

good point, and it will be differential noise too. Not to mention the coil would need to be very near to other circuitry it could easily interfere with.

That is definitely on my mind. I'd be looking for a low loop area coil and possibly try and come up with some kind of small, grounded steel shield box to hover it inside of.... And give all the rest of the high impedance sensitive front end it's own shielding.

Since I can make it in my garage I can make something I'd never be able to afford to mass produce.

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mediatechnology
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Re: Dielectric Absorption

Post by mediatechnology » Fri Jul 20, 2018 9:55 pm

The values Joe and I came up with IIRC were around 10µH in the mic preamp but to implement an RIAA pole would be expensive and hum-prone.
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KMN
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Re: Dielectric Absorption

Post by KMN » Sat Jul 21, 2018 1:10 am

It'd be somewhere around a mH.

In order to get the best emi immunity, wire gauge should be as small as possible to enable optimal constructions of a smaller loop area. Up to maybe ten ohms or so series coil R is acceptable. Multilayer is fine.

What I've seen, off the shelf looks nowhere close to optimal for my app. I'd be winding it myself for sure. At least it seems like the construction would be as simple as it gets.

Might not be too bad, from one of my sweat shop suppliers, if I ever got the quantities up there. haha

This would be the type of thing it would be easy to kludge in and try but it sure sounds like having a plan B would be wise, in case this didn't work out.

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JR.
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Re: Dielectric Absorption

Post by JR. » Sat Jul 21, 2018 11:29 am

if you are winding it yourself is there any way to make it hum bucking (cancelling), without altering the primary function?

JR

KMN
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Joined: Sat Jan 20, 2018 3:49 pm

Re: Dielectric Absorption

Post by KMN » Sat Jul 21, 2018 10:36 pm

Hmm, or maybe I should say humm... I hadn't thought of that. I don't know how I'd stop myself from trying it now. Great idea!

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