SMD size copper foil capacitors?

[gentlevoice]

Hi all,

I wonder if one of you would know of an SMD size copper foil capacitor with a dielectric of NPO/C0G, polypropylene or PTFE? I have searched but haven't yet found any ... maybe they don't exist?

Thanks for any tips you may have

Jesper

 

[Johno]

Jesper,
I have radial polystyrene caps in my Onkyo cd player that show bright copper foil under the clear coating. Have not heard of anything similar in SMD however.
John

 

[gentlevoice]

Hi John - thanks for replying - but I'm mainly looking for SMD size types - and possibly small size copper foil/polypropylene/PTFE capacitors ...

Cheers,

Jesper

 

[Calvin]

Hi,

I haven´t hard of copper-film caps in SMD either.
Since the cap manufacturers rely on ´standard´ films, which are typically aluminum or zinc sputtered and since there´s no real advantage using copper in this application I doubt that anyone will manufacture such caps.

jauu
Calvin

 

[Johno]

There is the stacked film variety of SM caps - but these are, to my knowledge, always metalised film. And usually polyester.

 

[AndrewT]

they are selling MLCC in NP0/C0G ceramic.

 

[RayCtech]

I'm mainly looking for SMD size types - and possibly small size copper foil/polypropylene/PTFE capacitors ...

Cheers,

Jesper

Hi Jesper,

I have been searching for the same kind of capacitors and I expect for the same usage. I can send you some samples of the four candidates I have settled on - two copper foil and two silver mica - no SMD parts, but relatively small in size and if hand soldering it is easy to use SMD pads on the PCB.

 

[RayCtech]

they are selling MLCC in NP0/C0G ceramic.

Nickel witch is a magnetic material (at room temperature) are used as the inner electrode.

 

[marce]

And...
These devices are used in other sensitive analogue/digital equipment.

 

[RayCtech]

And...
These devices are used in other sensitive analogue/digital equipment.

Correct...

And when I replace them with non-magnetic capacitors the equipment still performs as specified...

The only difference are that the SQ improves..

 

[jcx]

Really? Blind, level matched, ability to switch fast?

(you don't have to just ABX with short listening/fast switching but it does improve discrimination of some sound differences in controlled testing - so you really need the capability so you can compare on several time scales)



and its likely the actual inner electrodes in monolithic mlcc don't have Ni, some are even Ag – but there may be a barrier layer of Ni plating under the terminal plating to prevent leaching during soldering

 

[marce]

I am talking about very sensitive stuff...
All things are magnetic one way or another, how can a bit of nickel in a small cap affect an A.C. signal?

 

[jcx]

how can a bit of nickel in a small cap affect an A.C. signal?

apparently in a way that doesn't show in "conventional measurements" - like harmonic distortion at -140 dB down

but there are components made for NMR machines – with no (ferro)magnetic materials at all

I will simply quote the results from Samuel Groner's thesis.

Distortion of capacitors at +20dBu on the capacitor, 1kHz

Polysyrene LCR components FSCEX 10nF - no visible harmonics above -153.4dB noise floor (none nada zilch)

Vishay MKP1837 PP film - same

Vishay COG/NPO - same, noise floor -142.5dB (ceramic BTW, this was 1nF which I assume is why the noise floor was higher)

Dick, I'm not being a trouble maker and I'm asking nice could you please show me schematically how to put a sine wave through a C with rectifying defects at the input to get the cancellation of distortion.

 

[RayCtech]

but there are components made for NMR machines – with no (ferro)magnetic materials at all

Interesting - do you have any info / links?

 

[gentlevoice]

Hi All,

- have just had a quite special morning riding my bike along the coast line of Aarhus where I live. The sun was rising and reflected against a thin layer of clouds with yellow/orange pastel colors. Wow! - I really find myself gifted living where I do ...

And then about the capacitors:

@RayCtech: Thanks (once more) for offering to help me with components I'll send you a PM about it shortly.

Interesting - do you have any info / links?

I've found these from Vishay that appear to be non-magnetic and possibly also have an interesting termination ("noble metals"):

http://www.vishay.com/docs/45128/vjnonmagneticseries.pdf

They're available in C0G types but as far as I can see not in a copper foil. Max value is 39 nF for the C0G types.

@jcx:

Originally Posted by scott wurcer .... I will simply quote the results from Samuel Groner's thesis.

Hi jcx ... Might you have a link to Samuel Groner's "thesis"? I searched for it yesterday but didn't really find any ...

And then a thanks to all for considering my question by answering

Jesper

 

[marce]

apparently in a way that doesn't show in "conventional measurements" - like harmonic distortion at -140 dB down

So nothing that is going to be audible.

NMR machines create very strong magnetic fields, hence you don't want ferro-magnetic materials in there, audio is a bit different.
I would love to see some hard evidence of such a tint amount of nickel affecting the sound, in a way that is audible.

 

[jcx]

yes Vishay lists nonmagnetic parts
2010 Super 12

Syfer (Cu):
http://www.google.com/url?sa=t&rct=...-chadCa7CqISIC4Uw&sig2=CQbLI59Dpd4BOX1a6y8gfw

 

[gentlevoice]

@jcx: Thanks for the tip on the Syfer capacitors - looking into it ;-)

Cheers,

Jesper

 

[RayCtech]

So nothing that is going to be audible.

NMR machines create very strong magnetic fields, hence you don't want ferro-magnetic materials in there, audio is a bit different.
I would love to see some hard evidence of such a tint amount of nickel affecting the sound, in a way that is audible.

Harmonic distortion are the very least issue that matters...

 

[RayCtech]

@jcx: Thanks for the tip on the Syfer capacitors - looking into it ;-)

Cheers,

Jesper

As they use / can use different dielectric materials further investigations into this will be interesting..