[mike s]

My earlier mention of Bob Pease led me to google him. I found this very interesting article that may help to explain why ancient PIO capacitors behave in a different way to modern (better?) capacitors. http://www.national.com/rap/Applicat...570,28,00.html

In the 1940s electrolytics were known to be noisy, so for low noise power supplies paper-in-oil was favoured, but I think by the 1960s they were rarely if ever used in that role as they were far too large - and probably too expensive.