Ah yes, maybe going to the MKP2 or MKP0 series, if i remember correctly or also selecting some lower voltage ratings.
Of course, when I had purchased that big 1uF WIMA MKP4 series, I tried to make sure to choose one of the series where they mentioned High Quality Audio use in the specsheet.
Of course, after a few years from that order (it was my first order ever from mouser), I am confident I'll be choosing the stuff a bit better.
Thanks for confirming!
About opamp bypass caps, some Kemet 100nF polyester should do the trick just nicely.
A guy, a while ago at the other place, mentioned these, which have just the right size to be able to easily put them with very short legs at the right op-amp pins:
https://www.mouser.it/ProductDetail/KEMET/MMK5104J63J01L165TA18?qs=LpuuGx8iR2T2b8brVibGLQ==
but there are also these (of same size) if some slightly higher voltage rating is needed:
https://www.mouser.it/ProductDetail/KEMET/MMK5104J100J01L16.5TR18?qs=IKDMbYZLynBNPbu4N6UnvA==
and I am seeing they aren't that different than what Alex/A.N.T put into my own Technics RS-B965 while modifying them, as op-amp supply bypass caps, as you can see at this picture here:
View attachment 74554