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Re: Audio Note power transformer [message #63070 is a reply to message #63015] Sat, 05 June 2010 13:01 Go to previous messageGo to next message
Frihed89 is currently offline  Frihed89
Messages: 30
Registered: June 2009
Location: Copenhagen, Denmark
Baron
It's possible. The old AN caps were made by Jensen and had leakage problems. The new AN copper foil caps are no longer made by Jensen. And even Jensen has discontinued the old production model. Their factory is not too far away, but I still prefer AN.
Re: Audio Note power transformer [message #63074 is a reply to message #63070] Sat, 05 June 2010 23:29 Go to previous messageGo to next message
Thermionic is currently offline  Thermionic
Messages: 208
Registered: May 2009
Master
I've used dozens of those old-model Jensen/Audio Note PIO caps, and have been fortunate that (to my knowledge) not one has ever failed in service. Of course, I observe some extra precautions when using PIO caps. I avoid using them where very high internal chassis temperatures are present. I also use carbon composition grid stopper resistors with them, as the composition media is a poor conductor of heat, and helps isolate them from heat conducted from the power tube socket.

Many PIO caps have poor thermal stability; when cold their DC resistance may be hundreds of megohms, but it plummets as they become hot. I once saw a Chinese-made PIO totally lose it just a few minutes after turning the amp on, due to heat conducted into it through its leads. You could see the results of the DC leakage as it increased; the power tube began to glow in a tiny spot or two, and then eventually hotplated all over. I replaced it with a Jensen, and about 5 years of daily use later, the amp is still doing well.

Thermionic
Re: Audio Note power transformer [message #63077 is a reply to message #63074] Sun, 06 June 2010 09:05 Go to previous message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

The capacitors that failed in my amp were the new production Audio Note caps. Not to take away any of the good information on the Jensens or on paper in oil caps in general. Just wanted to clarify.

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