Preffered film caps to replace ceramic caps?

rg12

Member
2010-08-10 3:52 am
I wanted to know which film caps do you recommend to replace
ceramic caps in my Pioneeer SA-7300 amp.

I need:
0.022
0.1
0.0056
0.0012

I prefer that it will be from the same series but i couldn't find those 0.0056 and 0.0012.

Which brand is preffered?

I need a place with international shipping (not mouser, the international shipping there is $40!).

Roi.
 
I'd sure want to know what those caps do. If they're NP0/C0G ceramics, you'll gain nothing by switching them to film and the increased size will actually be detrimental. OTOH, if they're some poorer grade of ceramic with higher losses, you could actually cause stability problems by going to a low D film. Everything depends on where they are in the circuit.
 

kevinkr

Administrator
Paid Member
I wanted to know which film caps do you recommend to replace
ceramic caps in my Pioneeer SA-7300 amp.

I need:
0.022
0.1very
0.0056
0.0012

I prefer that it will be from the same series but i couldn't find those 0.0056 and 0.0012.

Which brand is preffered?

I need a place with international shipping (not mouser, the international shipping there is $40!).

Roi.

Are you sure those are currently ceramic? I'd be surprised frankly if they were. There are a number of film caps that are encapsulated in an epoxy material that looks a lot like ceramic. These are usually shaped like "chiclets" (a pillow shaped chewing gum) and are often colloquially known as such. Usually they are green, red, or orange..

Wima would be a name that comes to mind immediately as a potential upgrade for "chiclets" or ceramic types.

Note that 0.0012 = 1.2nF(1200pF), and 0.0056 = 5.6nF(5600pF) both of which are standard values in film caps.

Also it is really helpful if your CV/User ID info includes the country you live in at the least so that we can steer you in the direction of parts you can likely get there.
 
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Anything green is film unless it's a disc and my guess is they're Mylar. If you can find polypropylene, you should benefit. If not, don't mess with 'em. Anything brown and round is a ceramic and if it's signal related and not marked C0G or NP0, changing it to poly would also help. I see some little blue things. If those are tantalums, get 'em outta there! Replace with high quality electrolytics to avoid possible shorts and board damage. Observe polarity! This sort of project is where I always recommend having a capacitor bridge handy. When you have a bridge you can check not only values, but dissipation factor. That will often give you a clue as to what type of cap is installed. It also avoids annoying and mysterious mistakes concerning values and even what something really is. Build or buy, but making mods without test equipment is hit or miss.
 

infinia

Member
2005-05-15 9:51 am
SoCal
I would strongly advise against random replacement of ceramics. Unless you have intimate knowledge of said design and the trade offs involved. Ceramics are superior to films in many applications still, even in audio. I reckon Pioneer audio design engineers know more than most here on this thread. If the parts voltage rating, HF ESR performance, and lead spacing is comparable, you might make an improvement. But were X7R ceramic caps are used, microphonics, value tol. and stability is rarely a highly desired spec. There are exceptions and compromises in any designs tho.
 

kevinkr

Administrator
Paid Member
Conrad those blue things look like tantalums to me too, and if so I agree that they should be replaced immediately with a high quality low impedance AL electrolytic.

The tone control caps a few of which appear to be ceramic may be safely replaced with film types.

The warning about replacing ceramics wrt to the power amplifier section are well taken, replacing the ceramic miller compensation cap in the PA VAS with a film could result in the destruction of the output transistors if it results in HF oscillation.

The OP list above only includes caps in the tone control circuits which should be fine.
 

infinia

Member
2005-05-15 9:51 am
SoCal
Global parts replacement, except maybe electro caps ( by competent people ) rarely results in improvements. Full Stop
Each and every part has a function and has been agonized over by the original engineers line by line. If you plan on doing it over again piece by reference designator piece with an experienced design engineers then OK.
 

rg12

Member
2010-08-10 3:52 am
The 4 blue tantalums you see there are the 4 caps that are directly
in the signal path and has been replace to Mundorf MKP (Metalized Polypropylene) and they sound great.

I will locate all tone control caps and mark them in the photo and repost
the photo to make sure with you guys that it will be fine to mod them.
 

rg12

Member
2010-08-10 3:52 am
When you use caramic use NPO or COG, they are low distortion. If you want to replace the ceramics i made the best experience with siver mica. The layout matters too and when you replace the ceramics with big foils you can screw up the layout badly and end up with oscilation.

What is NPO and COG? brands? types?

What does oscillation cause?

And what will be gained by replacing ceramic with ceramic like you suggest?
 
NPO or COG material is the best ceramic material in use for ceramic caps. It does also have the lowest dielectric constant so caps made that way are bigger then caps from less good material. NPO/COG have much less distortion then other ceramics and value is stable over temperature. I whould expect a sound that is cleaner and less tempramental using this caps. Oscilation is caused when the circuit ( i asume it is a wideband circuit ) is terminated at the PSU side by a varying impedance over frequency. For example an unfortunate combination of cap values and layout could result in an output impedance of the PSU that looks like a comb filter over say 100kHz and goes wildly up and down. A high speed circuit is only stable when PSU impedance is flat and low to high frequencies. You could call an amplifier a modulated power supply and the you may get closer to understandig high speed electronics.
 

rg12

Member
2010-08-10 3:52 am
NPO or COG material is the best ceramic material in use for ceramic caps. It does also have the lowest dielectric constant so caps made that way are bigger then caps from less good material. NPO/COG have much less distortion then other ceramics and value is stable over temperature. I whould expect a sound that is cleaner and less tempramental using this caps. Oscilation is caused when the circuit ( i asume it is a wideband circuit ) is terminated at the PSU side by a varying impedance over frequency. For example an unfortunate combination of cap values and layout could result in an output impedance of the PSU that looks like a comb filter over say 100kHz and goes wildly up and down. A high speed circuit is only stable when PSU impedance is flat and low to high frequencies. You could call an amplifier a modulated power supply and the you may get closer to understandig high speed electronics.

Well, thanks for the info, i understand the stuff about the ceramic's material types but i didn't understand anything bellow that.

Thanks alot anyway.
 

infinia

Member
2005-05-15 9:51 am
SoCal
It's only really useful speaking about parts specs in relation to their circuit functions. Like anything it's all about trade offs or balance.


Yes there are low K ceramic dielectrics that behave themselves. but they are only economical in low values, say below a few hundred pF. Yes they are great for critical audio filters and timing circuits, but they can get mighty pricey tho, again in larger sizes > 500 pF. Not too useful for DC supply bypass , snubbers, non critical low impedance RF filters. For HF filters small size is important to keep SRF high, and NP0 C0G are much bigger than their high dielectric counterparts. X7R ceramics will still be around for a long time.
FWIW
Forget replacing 0.1 and 0.01 uF surface mount or ceramic discs with NP0.
I would venture a guess that the Pioneers amps freq. compensation caps are already NP0 / C0G. They are easier to make to low value tight tolerance caps anyway
 
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I did not say he should replace the SMD caps with COG. I just wanted to inform about the performance differences. When the Pioneer is working fine i see no reason to replace anything. Could be that there are some primitive Elcaps in the signal path and that is where i would try to improve. There are some good Elcaps like Elna Silmic2 and Nichicon Muse that are very good in the signal path too. I whould bypass them with a 1 to 10nF of good qualtily though . At extreme high frequencies the losses in the Elcaps go up and although we are not talking about frequencies under 20kHz difference intermodulation product could get audible if the Elcaps are not bypassed but giving advice about tuning on this forum where a lot of scientifically oriented people express their opinions i found that talking about very small subjective differences usually ends up in fierce discussion with the result that the thread is closed so any ( tiny ) subjective improvement you can wring out of your component is your personal enyoyment. I hear diffences that i can not measure and i can life with that. I whould never insist though that others hear the same diffences or it could be that i am just a victim of my own illusion.
 

infinia

Member
2005-05-15 9:51 am
SoCal
Hi
I don't think you are wrong , I'm just trying further some generalities which are "always" (pun intended) dangerous. I don;t think there are any SMD here anyways.

I just have a deep concern when inexperienced people go willy nilly part exchanging based only on a caps dielectric matériel due to rumors and innuendos. Its not so simple as a bad cap good cap thing. I had visions ( delusions?) of some newer folks running to replace all ceramic caps with NP0 because some Guru says he has them in his gear.
 
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rg12

Member
2010-08-10 3:52 am
OK here is a nice pic of the amp with the treble and bass caps
marked in red: http://www.milkbands.co.il/caps.jpg

The disc caps are for the treble and the green ones (NP1) are for
the bass.

Also, the right red circle shows the same cap pattern but for the balance
pot. If i mod the bass and treble, would i benefit from replacing the balance caps too?

Why don't they write the capacitance value on the disc caps and NP1 caps? i found them by the copper tracks and not by the values (because
they only have numbers that aren't related to capacitance value as far
as i can see).

What do you recommend doing to improve the sound? to replace them
to which type? Also, i always place the bass pot very low (3 out of 10
in the marks of the face panel) because the bass is very "closed"
very "smudgy", so what can i do to make it more accurate and punchy?

About the treble...i don't like those disc caps...

What do you guys think?
 
Why don't they write the capacitance value on the disc caps and NP1 caps? i found them by the copper tracks and not by the values (because they only have numbers that aren't related to capacitance value as far as i can see).


I think you need to read up some on Capacitor "BASICS" and at least learn to properly identify the different types before attempting to replace them.
Here is a good starting place --->http://www.amqrp.org/reference/na5n_cap_guide.pdf

Ceramics usually only have #'s printed on them like "102" "103" etc... and these correspond to a specific value - .001uF; .01uF etc..etc... I won't go into all the derivations... Just scroll down on the link I provided and you'll see a table with the most commonly used/seen values.




What do you recommend doing to improve the sound? to replace them to which type? .....what can i do to make it more accurate and punchy? About the treble...i don't like those disc caps...
What do you guys think?


I don't think you're listening to what "other" more experienced members are saying! Not EVERYTHING needs to be replaced/changed to achieve a "better/improved" sound! Ceramics STILL have their uses.

If you're just hell-bent on changing them, regardless of what "others" are advising, then buy a bunch of different "types" (same value of course) and swap them out, listen to the way "it" sounds and repeat! You will be VERY surprised at how little they differ, if at all!





J-