Are NOS Russian PIO caps rated in AC or DC volts?

[EricS]

I've been looking at some of the NOS Russion PIO caps - the MBGO and the KGB types that come in rectangular metal cans. It seems that finding higher uF values with 600v ratings is rather difficult. This makes me wonder, are the voltage ratings that are printed on the cans in AC or DC???

Anyone have any insights here?

Thanks in advance.

[galyons]

The ratings are DC. Much depends on your definition of PIO, (Paper in oil).  MBGO are not PIO.  They are metalized paper and wax.  KGB are PIO, oil impregnated paper and aluminum foil.  IMO, KGB and K40Y are the best of the Komrade Kaps to use in the signal path.  But there are size limitations.

The higher the voltage rating, the thicker the windings. The higher the capacitance, the bigger the cap.  So the size of the cap has physical limits. 

I have some 600V KGB in, I think 6uf.  They are huge.  The MGBO were available in higher voltages and capacitance, but harder to find now.

Cheers,
Geary

[EricS]

Thanks, Geary.  This is kind of what I was expecting to hear, but I was hoping to hear otherwise.  I am aware that the MBGO are metalized paper and wax.  I have a few of each type and I have noticed that finding KGB caps in 600v ratings with larger uF values is not so common.  I think 6uF is the largest I've seen in 600v.  I've seen a few 1000v floating around, but these seem to be limited to 4uF.