Ceramic capacitors

[Rod]

What are the best sounding ceramic capacitors? any type or brand to look for?


What could be the capacitors used by Marshall in his dsl100HR, has you can see in the attached picture bellow?

https://freeimage.host/i/dsl-g5e.JK2VmF

[The Dude]

Those look like tantalum caps to me- not ceramic. Aside from that, no comment. The internet is full of "what caps sound best?" debates. I won't start another one.

[Pedro Vecino]

Monolithic/multilayer ceramic capacitors.

[loudthud]

For small values, try to find an NPO temperature rating.

[SoulFetish]

For small values, try to find an NPO temperature rating.

took the words out of my mouth....
to follow up on that - Rod, it can be difficult to know what to buy when there are so many different opinions on capacitor "sound". While there are no shortage of opinions on the subject, facts often rarely enter the discussion. Hopefully this answers some questions about which ceramic capacitor sounds best.

Ceramic caps are super common in most all electronics. But, there are some factors which can severely affect their level of capacitance. These are temperature, applied voltage, and age. One other thing is how susceptible they are to a piezoelectric effect (microphonics). How much these factors affect different types of capacitors,( ie C0G, X7R, Y5V, etc) is wildly different. Because of this, ceramic caps fall into 3 different types of categories: (WARNING: Electronics Standards Ahead, try and stay awake...)

• They are designated classes I, II, and III.

Class I include the type Loudthud mentioned, NP0. Its also know as C0G (By the way, that is a numerical "0", not upper case "O". Who knew?). For the sake of a shorter post, for our purposes, these capacitors are the heroes of ceramics. They virtually have no change in capacitance over there rated temperature and because of their unique composition, they are not prone to microphonics, like other ceramic caps.
The other classes, types II and III, are labeled according to how much there capacitance changes with lower and higher temperatures - 1st letter lower, second digit higher temp, 3rd digit % how much capacitance changes.
You can see that for common types, the value of capacitance can change from 15% to 70%!!
Plus, depending on their material composition, capacitance can change up to 70% with applied voltage .

So, sounds to me like C0G/NP0 are way better than the other types.

[Rhodesplyr]

Yes, NP0/C0G types are the best ceramic types in terms of being closest to being ideal capacitors. They are extremely stable with respect to temperature and age. They are similar in many ways to mica caps. Their downside is that they tend to be physically large, so tend only to be found in smaller picofarad values.

To make ceramic capacitors in larger values without getting huge, the ceramic dielectric is doped with various compounds that increase the dielectric constant -- at the price of introducing a voltage coefficient of capacitance (capacitance changes with applied voltage), changes of capacitance with temperature, as noted above, changes of capacitance with age, and piezoelectric effects, acting as microphones or, in some cases, as tiny speakers.

In terms of guitar amps, the question is how much these nonlinearities matter. Z5U ceramic caps are common in some guitar amps from the late 50s and 60s. I worked on a Supro/Wards Airline amp that was full of them, and its owner loves it.

[SoulFetish]

Yes, NP0/C0G types are the best ceramic types in terms of being closest to being ideal capacitors. They are extremely stable with respect to temperature and age. They are similar in many ways to mica caps. Their downside is that they tend to be physically large, so tend only to be found in smaller picofarad values.

To make ceramic capacitors in larger values without getting huge, the ceramic dielectric is doped with various compounds that increase the dielectric constant -- at the price of introducing a voltage coefficient of capacitance (capacitance changes with applied voltage), changes of capacitance with temperature, as noted above, changes of capacitance with age, and piezoelectric effects, acting as microphones or, in some cases, as tiny speakers.

In terms of guitar amps, the question is how much these nonlinearities matter. Z5U ceramic caps are common in some guitar amps from the late 50s and 60s. I worked on a Supro/Wards Airline amp that was full of them, and its owner loves it.

It is an interesting question. It would be interesting to see those instabilities contributed to some desirable effects.
The interesting thing to me is the how the ceramic dielectric constant changes with applied voltage, this includes AC voltage, and not strictly it's DC bias. If the tolerances were fairly predictable between samples, you could probably leverage this effect for phase shifting and filtering applications.

[mozz]

Some of those ceramic disk capacitors from back then were about the cheapest cap you could buy. But many of them are still working good. I think they distort the sound or cause phase shifts or something, but if it's in the creation part of music, that what gives it the sound we like. I have used ceramic caps in a few pedals and they were microphonic. I don't think tolerance matters all that much. If you have a decent LCR meter, measure the dissipation factor. Ceramics are terrible, poly and film caps are much better and polystrene and mica are great. You will see polystrene in such original pedals as the dallas rangemaster on the output. I have old 50's 60's Vitamin Q caps and similar others and they test great and blow away anything modern as to tolerance and super low dissipation. Bumble bee, black beauties, and those blue fender molded caps test like crap, but you want them in certain applications.

[Rhodesplyr]

It is an interesting question. It would be interesting to see those instabilities contributed to some desirable effects.

The other rule of capacitors is that you hear their effects far more if their value places them in the middle of the audio frequencies you're listening to. If you had, say, a 0.1uF ceramic cap coupling tube stages into a 1M grid resistor, the high-pass frequency would be so low that any capacitance change with applied signal would likely be inaudible. In a tone stack, you might notice some effect.

[Leo_Gnardo]

What I've found in disc caps, especially the larger ones (say 8mm diameter or more) - some have a mechanical resonance (mictophonic effect) that has little to do with their filtering function. Tap suspect caps lightly with a chopstick for instance, hear "plonk plonk plonk." This can lead to resonances - maybe some wanted, some others not so much - in combo amps, or as an amp head is shaken by being atop a speaker cab, or if the sound field is great enough to shake the caps just from the racket onstage. A glob of RTV can damp the noise from a mechanically resonant cap. Or - replacing it with a cap of different construction pretty well eliminates the resonance. Occasionally I find a "clacky" resonance in orange drops - say 600 to 2KHz. Perhaps this is part of their perceived sound "quality".

Tap your caps, maybe you'll hear something you like. Or don't. Then you can take measures to deal with the sound artifacts they create. Or not.