Gah, I still have trouble figuring out small cap values. I pulled this ceramic cap from a 50 year old amp. It is marked "500". Is that its cap code, making it a 50pf cap? Or is it a 500 pf cap, plainly marked? If it was marked 501, then I guess it would be a 500pf? Now, how about this one - marked 1700? I can read these if they have a last number that isn't zero. 472, 501, etc. But the ones ending in zero mess with my head.