Elna Silmic II or Elna Cerafine?

[rg12]

Im going to replace the caps in my whole amp.

I wanted to know if it's ok to put the same series in the whole amp.

I narrowed it down to two options Elna Silmic II or Elna Cerafines (Silk vs. Ceramic Electrolyts).

What do you guys preffer?

[indianajo]

Ceramic is useful for speeding up response of power supplies, parallel to the thousands microfarad power supply caps. Ceramic is useful in picofarad sizes for RF oscillation elimination. Ceramic NPO dielectric is not usually used for audio coupling caps, filter caps etc. There usually people use plastic film dielectric below 10 uf, like polyprophylene, polyethylene, polyester. Above 10 uf, electrolytic is required by size usually. When buying electrolytics, be sure to buy caps rated 2000 hours expected life or higher, and recently manufactured. Mark the plus end of the PCB before removal of electrolytics, if you get it backwards they explode. The selector table of your distributor should show the design life, if not you can download the datasheet from his link, or from datasheetcatalog.com. Size is important too, the datasheet will show that.
Silk has not been used as a capacitor dielectric since the 1920's, you should look at the datasheet to find out what it really is.
Dielectric is the film, paper, or plastic they put between the metalized plates of a cap. Electrolyte for caps, in english, is the fluid they put in an electrolytic cap (usually borax water).

[rg12]

For both from this series they say it's 1000 hours.

They are both high quality audio cap series of Elna.

The Cerafine series are ceramic electrolytic caps made especially for audio,
they are not disc shaped.

They don't write the manufacture date in the website, what can i do?

[indianajo]

To get fresh caps, buy from an authorized vendor and pay full price. Stale caps come from resellers, surplus houses, e-bay, craigslist, etc. Authorized distributors will put a flag next to the part indicating a "sale" if the part is old. As I said, it is electrolytics that get old fast. Ceramic and film don't age much. If ceramic is cpo dielectric, use only for the purposes listed above. z5u dielectric is marginally acceptable for interstage coupling or rolloff filtering, but John Curl doesn't like even that use. Hours aren't real important on ceramic and film dielectric caps used in audio, the datasheet spec on film and ceramic are usually talking about radio transmission or some heavy current use. Expected life means a lot on electrolytic caps.

[rg12]

A 1000 hours is low for electrolytic? it's two high series high quality known caps.

Can i use the silk (Elna Silmic II) electrolyts for the whole amp?

[indianajo]

It's a free world, buy what you want. I've got a Sprague 516D108M050QS6AE3 I bought last year, 1000 uf @ 50VDC, 2000 hours life predicted. I've gotten 25 years out of sprague previously. Sounds like you are in europe, check the farnell.co.uk website for full list of what hours life are available for any given size and voltage. Then again the prediction isn't everything, either. I've gotten 25 years out of Sprague atomlytics, and they have no hour prediction at all. I've got an Apex Digital TV converter bought last year at W***m******, obviously had bad electrolytic caps the day I bought it because there are lines on the screen that go away after a ten minute warm up. Saving you money every day.

[wintermute]

After looking at the datasheets (I can't remember what was the differentiator, perhaps just some marketing blurb), I chose silmic II's. Nelson Pass recommends them too

Tony.

[rg12]

I want to buy the Silmic II but they don't have 330uf 63v that i need and it screws up the whole series of the amp when every cap is silmic except for that one an two small ones.

Any suggestions?

[wintermute]

Try a different supplier, the Silmic II does go to 63V in the 330uF according to the datasheet.

Also it was the attached part of the datasheet that made me lean towards the silmics over the cerafines. That and the tan theta being lower. The cerafines are the ROA series...

If you can't get the silmics in the size you want, rather than getting the cerafines you could consider a nichicon KZ. They go up to 100V in 330uF and are probably closer in performance to the silmic II than the cerafines (note I'm going purely off the stated tan theta on the datasheets here, not off any direct experience), apart from also being an "audio" marketed cap.

When I did my amp abiout 5 years ago, I used a mix of Panasonic FC's and rubicon ZL's I think (it probably took a month or two of agonizing over datasheets to come to that decision). I just used what I thought was the best for each particular section (out of what was easily available to me). I also replaced the larger ceramics with wima fkpII's in reality this probably made more of a difference than anything else

Tony.

[rg12]

I don't have the knowledge to know which ones i prefer to be one series
and which one to be another.

It just drives me crazy knowing that the series doesn't cover the 0.22uf cap
and 330uf 63v cap i have (about the 330uf 63v i checked all over for the silmic II).