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Old 27th August 2010, 06:57 AM   #1
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Default Preffered film caps to replace ceramic caps?

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.
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Old 29th August 2010, 05:38 PM   #2
Minion is offline Minion  Canada
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If these caps are Not used in a tone controll section or as active filters then you can get away with useing a slightly higher value , like 0.0015 or 0.0068 .....


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Old 29th August 2010, 06:12 PM   #3
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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.
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Old 29th August 2010, 06:58 PM   #4
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They are in the tone control.

Here is the schematic: Caps numbers: c27 c28 c29 c30 c31 c32 c33 c34
http://www.milkbands.co.il/Pioneer-SA-7300-int-sch.pdf
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Old 29th August 2010, 07:23 PM   #5
kevinkr is offline kevinkr  United States
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Quote:
Originally Posted by rg12 View Post
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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Last edited by kevinkr; 29th August 2010 at 07:31 PM.
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Old 29th August 2010, 08:29 PM   #6
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I can see a few green and red pillow shaped components, here is the pic,
you can see them on the bottom left and bottom right (on the right two
big red ones):
http://www.milkbands.co.il/P8080006.JPG

So if they are film, will something be gained if i replace them to a new good quality cap?

Im ordering everything from digikey and parts connexion
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Old 29th August 2010, 11:45 PM   #7
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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.
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Old 30th August 2010, 12:18 AM   #8
infinia is offline infinia  United States
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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.
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Old 30th August 2010, 12:21 AM   #9
kevinkr is offline kevinkr  United States
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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.
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Old 30th August 2010, 12:30 AM   #10
infinia is offline infinia  United States
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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.
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