Need guidance to replace low values ceramic caps in XTA446

[santodx5]

Halo All,

I want to replace these yellow caps ceramic 220pf in my XTA digital management. They are use to filter noise.

Just want to confirm if this will make any audible benefit / less noise.

Here are photos of the ceramic and specs.

The replacement I was thinking are:
1. AMCH Series Film & Foil Capacitors
�Å�‚‹‰ƒI�[ƒfƒBƒI—p ’Y‘f”í–ŒŒÅ’è’ï�RŠí AMRA Series
2. Russian SGM Silver Mica

Which one do you think will give better benefit and should I change them?

Thanks,
Dan

 

[DF96]

I take it you have studied the circuit diagram, identified exactly what each of these capacitors does, and concluded that the original designer specified the wrong type of capacitor for this duty?

Please note that before we can give a sensible answer to your question we would need to go through the same process ourselves.

Ceramic caps are often used as part of the supply rail decoupling arrangements for integrated circuits. They are good for this, which is why they are used. This may or may not be what you mean by "filter noise". At 220pF a ceramic cap could be NP0/C0G (so chosen for low loss and high stability) or possibly a high-k ceramic (so chosen for higher loss and unimportant stability). In either case (assuming the original designer got it right) there is no advantage in changing them to something less appropriate.

 

[santodx5]

Im not knowledgeable enough to read schematic. Most of my mod is to replace caps, resistor, regulator, and basic stuff.

Ive been reading the forum and many state that ceramic has high dialetic absortion. Also it is piezo electric.

So i wonder if im to replace them with polypropylene will ad some benefit. Even slight benefit is fine as i will replace all caps as well. In the end the sum is higher than the parts.

Thanks

 

[DF96]

"Ceramic" is not a dielectric; it is a whole family of dielectrics with widely different characteristics. Some may be appropriate, some may not.

As you don't know what these caps are used for in the circuit you are not in a position to judge whether the original designer specified the correct type. In the absence of evidence to the contrary, it is wise to assume that he was more likely to choose the correct cap than you are.

DA is not harmful. Only some ceramics are piezoelectric. Replacing those caps with polypropylene will almost certainly do no good, and could do harm. Why do you want to do this? Did you read somewhere that polypropylene caps are 'good for audio'? That is a meaningless concept without a whole lot of context. In electronics context is everything.