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K40Y-9: Questions And Comments

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Troncones

Troncones

Member
Joined 2009
These are Russian PIO Caps. Does this symbol indicate the construction of the Cap? Which is the preferred In (Driver Plate) and Out (Output Valve Grid)?

I want to orient them before I run them very long. I have tried them both ways and can't hear a difference.

These Caps sound good. I think they will sound even better after some hours are put on them.
 

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ryuji

Member
Joined 2011
They get pointed in direction of higher potential, at least that its what my friend that uses them told me to do. He also said both ways is fine for it but the way I just described is less distortion

I been using them on my amp for quite some time that way without trouble
 
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Bob01605

Bob01605

Member
Joined 2007
tubes4hifi.com/bob.htm
I have often wondered what a Russian K40-Y PIO cap looks like inside. Last November I took one apart for a closer look. They have plenty of "oil" on the inside inpregnated into some thin yet strong paper. I don't know what kind of oil it is but I did get some on my hands and found out that it did not wash off easily. The oil has no odor that I could detect. Inside the metal case is a thin cardboard that is used probably to insulate the inside of the cap from the outer metal case. Once this is removed there appears to be a "jelly roll" of the oiled paper and aluminum foil. The oiled paper is on the inside and a very thin sheet of aluminum foil is on the outside. I cannot be sure that the metal is aluminum but it looks like thin aluminum foil. Whatever it is, it is non magnetic.

I have used over 1500 of these K40-Y caps in the past 5 years and not one (to my knowlege) has ever failed. They are supposed to be + or - 10% but I have never found one to be off by more than even 5%. I have used the .22 uF @ 1000 volt and .22 uF @ 630 volt. Once broken in for 100 to 200 hours of play, these are fine sounding caps.

Bob Latino

RussianPIO800.jpg
 
M

mace1337

Member
Joined 2005
Yeah these caps are pretty great. Too bad the higher voltage and capacity ones are drying up.

I can confirm them containing PCB's, so use gloves if you feel the need to cut them open.

Even better are the FT-series teflon caps. Great clarity. Too bad they are so frickin huge.
 
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