Hi
Mr. Marsh's excellent capacitor article from years ago suggested that low-value C0G-NP0 caps were low distortion and acceptable for use in audio amps. It seems today that it is almost impossible to buy old-fashioned single-layer ceramic caps as everything is MLCC. If the value is <100pF and the dielectric is listed as C0G-NP0 is the cap still acceptable if it is also MLCC?
MLCC = multi-layer ceramic cap
Mr. Marsh's excellent capacitor article from years ago suggested that low-value C0G-NP0 caps were low distortion and acceptable for use in audio amps. It seems today that it is almost impossible to buy old-fashioned single-layer ceramic caps as everything is MLCC. If the value is <100pF and the dielectric is listed as C0G-NP0 is the cap still acceptable if it is also MLCC?
MLCC = multi-layer ceramic cap
Not the NP0/C0G types, but 220 nF models are available for about 2 to 4 euros a piece. Digi-Key even has one 2 uF type, but it costs euro 217.42:
https://www.digikey.nl/en/products/...AxTj36QQAVQljeAeRQBZHGiwBXETjnyD+gDCigDinLJAA
https://www.digikey.nl/en/products/...AxTj36QQAVQljeAeRQBZHGiwBXETjnyD+gDCigDinLJAA
Here is a good article from a guy at TI who measured microphonics.
https://e2e.ti.com/blogs_/archives/...sts-microphonics-in-ceramic-capacitors-part-1
https://e2e.ti.com/blogs_/archives/...sts-microphonics-in-ceramic-capacitors-part-2
Ed
https://e2e.ti.com/blogs_/archives/...sts-microphonics-in-ceramic-capacitors-part-1
https://e2e.ti.com/blogs_/archives/...sts-microphonics-in-ceramic-capacitors-part-2
Ed
The blog tests X7R dielectrics, which are also non linear with voltage.
COG/NPO has similar microphonics to film types. All capacitors have some when DC biased
Hi Guys
I have had bad experience with ceramic caps in SMPS, which is why I am suspicious of the MLCC construction. Does anyone know if the C0G-NP0 over-rides the MLCC for distortion in audio amps?
I have had bad experience with ceramic caps in SMPS, which is why I am suspicious of the MLCC construction. Does anyone know if the C0G-NP0 over-rides the MLCC for distortion in audio amps?
C0G is fine. In addition to not being microphonic, their use in frequency compensation means that poles should be outside of the audio range (if done right).
Ed
Ed
The issue with ceramic caps is the dielectric is ferroelectric, so it has dielectric hysteresis, this imparts distortion as energy is lost to heat each time the polarisation changes. This will distort the waveform regardless of the number of layers.
Not true for COG/NPO, which have very low dielectric loss and hyteresis
They are better than most plastic film types
https://www.kyocera-avx.com/products/ceramic-capacitors/surface-mount/c0g-np0-dielectric/
I recall a slide deck by one of the founders of Audio Precision that indicated that C0G/NP0 capacitors outperform film capacitors.
You can use X7R types as well as long as you don't impose too much audio signal across them. Also, if you do go that route, choose a physically large capacitor rated for a higher voltage (so 50 V even if you only have, say, 10 mV of audio signal across it). Obviously if you're aiming for -140 dBc THD this approach is out, but for lower performance stuff it's fine.
Tom
You can use X7R types as well as long as you don't impose too much audio signal across them. Also, if you do go that route, choose a physically large capacitor rated for a higher voltage (so 50 V even if you only have, say, 10 mV of audio signal across it). Obviously if you're aiming for -140 dBc THD this approach is out, but for lower performance stuff it's fine.
Tom
This
There is no technical justification to use film capacitors over NPO. Films look nicer and impress, but that is all
So I went through my volumes of Linear Audio, and found the article here:
Bateman, C. (April 2015.) "Capacitor Sound Revisited" Linear Audio of Turnhout,
Belgium, Didden, J. Publisher. (Vol. 9, P. 149-170).
This article test the following caps:
470 PET Polar wound
MKS2 PET Polar wound
MKT PET Polar stacked
SMR PPS Non Polar Wound
Some new issues cropped up with former good named manufactures that have been
taken over by other companies. Some caps also had quality issues, etc.
Bateman, C. (April 2015.) "Capacitor Sound Revisited" Linear Audio of Turnhout,
Belgium, Didden, J. Publisher. (Vol. 9, P. 149-170).
This article test the following caps:
470 PET Polar wound
MKS2 PET Polar wound
MKT PET Polar stacked
SMR PPS Non Polar Wound
Some new issues cropped up with former good named manufactures that have been
taken over by other companies. Some caps also had quality issues, etc.
Hi All,
Just found this thread and was wondering if anyone knows how to find/select the NPO/C0G MLCCs with the lowest dielectric constants? To my memory NPO/C0G capacitors have dielectric constants ranging from appr. 8 - ~30, and I would prefer to find the types with the lowest dielectric constants ...
I reckon thickness might be a selection criteria or thickness combined with voltage rating but over time I have found virtually no information about which NPO/C0G MLCCs may have the lowest dielectric constants. Anybody knows about this?
Cheers & thanks for considering,
Jesper
Just found this thread and was wondering if anyone knows how to find/select the NPO/C0G MLCCs with the lowest dielectric constants? To my memory NPO/C0G capacitors have dielectric constants ranging from appr. 8 - ~30, and I would prefer to find the types with the lowest dielectric constants ...
I reckon thickness might be a selection criteria or thickness combined with voltage rating but over time I have found virtually no information about which NPO/C0G MLCCs may have the lowest dielectric constants. Anybody knows about this?
Cheers & thanks for considering,
Jesper