PIO cap problems - World-Designs-Forum

Phil Y · #1 29th July 2011, 06:52 PM

Hello all,
I notice lately there has been several cases of people having problems with leaky PIO caps. The more knowledgeable of you seem to suggest that this is a well known problem with this type of cap.
What I was wondering was, is this a problem with all makes or are some ok and others to be avoided? I have one pair of PIOs, in my Phono 2/3, the 0.1uFs. Should I be expecting them to fail at some point?

Regards, Phil.

John Caswell · #2 29th July 2011, 08:24 PM

Hi Phil,
No don't panic. Over the years I have used many and have not had any problems. It is just bad luck that some people have had problems. Just accept that things fail and when they do, if they do, replace them and carry on.
There is a disease going the rounds that says if "X' is bad, anything like "X" is also bad. This of course is garbage, I shouldn't worry in the slightest because if you did you would not do or buy anything but take to your bed and die of bedsores:-) I look at life with the basic principle "You can't win".

John

Richard · #3 29th July 2011, 10:23 PM

Yes...

change them to polyprop just in case...

Seriously, they can become mechanically leaky - the oil leaks out and failure follows, and/or electrically leaky, when they start to pass DC.
There have been several instances on here but none I can remember of plastic caps doing similar. You might want to read this article by AudioNote, I have the paper/coppers and am thinking of just changing them out to plastic and having done. On the other hand you may well think the sound is worth the risk so each to their own as usual

http://www.audionote.co.uk/comp/cap_paper.shtml

bob orbell · #4 30th July 2011, 08:50 AM

Interesting link Richard, pricey little blighters arn't they. BOB

Ali Tait · #5 30th July 2011, 11:36 AM

Yes, a bit pricey as caps go, but they are very good. I have used them for years with no problems.

Phil Y · #6 30th July 2011, 12:45 PM

Interesting article Richard,
and refreshing to see a company that owns up to having a problem with one of its products. The caps I have are AN tin foils so not the ones referred to in that article.
I think it would be interesting if everyone who has problems with PIOs reported their make/type and approximate purchase date. That way we could get an idea if the problems are global or localised so to speak.

Regards, Phil.

bikerhifinut · #7 30th July 2011, 09:13 PM

My feeling is that all PIO's have a finite life.
You are trading off sound quality against service life.
It's the sealing arrangements on the lead outs I guess which allow the oil to leak out or evaporate? A real problem on old TCC etc stuff in vintage amps and why you should junk all the PIO original caps in your old leaks and quads.
I would imagine the modern stuff has a better life due to better sealing materials.
I confess to preferring polyprops or teflons, I like the "faster" modern sound.
So, my take is this, you have to decide whether its worth your cash to use PIO's because you like the sound quality.
An analogy might be the reason why I accept I will have to shell out between £400 and £600 every 3 years or so for a new MC cartridge because I simply can't do without it!

Andy.

Phil Y · #8 31st July 2011, 11:23 AM

It is a question of degree,
Old TCCs or whatever in vintage gear are at least 45 years old so they are entitled to be past it. If there was a warning on some caps I was buying saying "WARNING THESE CAPACITORS WILL ONLY LAST 45 YEARS" that is not going to bother me as by then I will probably be in an old peoples home dribbling down my shirt. Where as, if they are only going to last 5 years I would not touch them. That is why I thought people reporting their findings would be interesting.

Regards, Phil.