K40Y9 that you have are .22uf/1000V; FT-3 is .1uf/600V; FT-1 is .01uf/200V. Other values and voltage ratings are available on Ebay. All are OK for electronics within their voltage range. The russian seller claims to have tested FT-1 .01uf/200V out to 1000V.
If you don't want to wait for break-in of FT-3, put them all in parallel and wire the parallel pack in series with an AC load such as 75W or 100W lightbulb. Give them several weeks like that.
To hear K40 at its best, clip off the steel leads and replace with audiophile wire soldered to the stubs left protruding from the glass ends. BTW these mil spec PIO are hermetically sealed and should never leak.
If you don't want to wait for break-in of FT-3, put them all in parallel and wire the parallel pack in series with an AC load such as 75W or 100W lightbulb. Give them several weeks like that.
To hear K40 at its best, clip off the steel leads and replace with audiophile wire soldered to the stubs left protruding from the glass ends. BTW these mil spec PIO are hermetically sealed and should never leak.