I must notice that you mention MP as "paper in oil". Sorry, it's Metal-paper MP=Metal(foil) Paper with Tar as an dielectricMS Vienna said:I have no answer to the initial question, but I have compared various old "PIO" capacitors.
Bosch and Siemens "MP" are very high resolution but pretty neutral - don´t really add coloration or "mojo", if you like that expression.
Eastgerman RFT "MP" in the same dimension have equal resolution but slightly more pleasant coloration. They add some shiney midrange richness. I actually changed the Bosch and Siemens MP´s in my microphones to RFT´s. Those are still available on ebay.
The usual Russian PIOs are a bit better than good quality modern film caps but don´t come near the German ones, at least for my personal sense of aesthetics. But cheap and available.
I am taking here about application as op coupling cap in tube microphones. Results in other apps may differ.
My experience with low value Sikatrops (beige ceramic tube) from Siemens, Hydra ect. in tube mic circuits is that they are very high resolution, very low coloration. No "mojo" whatsoever. Used them for a while but eventually threw them out. Those are sometimes referred to as "PIO" as well.
I hope that´s helpful.
thekid777 said:Hi,
what is the cap made today which sounds the closest to these old bosch PIO?
Thanks!
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