My report in regards to my issue described above (quiet hiss about at 900hz) which i've got after applying Muratas which I had then partially fixed by applying 220uF caps .

Today I've shortened power cable between original Caiman PSU to Caiman to about 40cm (15,7") and removed 220uF caps from Muratas. My hiss issue is completely back so there is something weird on it as shortening path between PSU and Muratas should be solution instead of caps workaround I've done before.

I'll let it in this state until cheapest laboratory linear PSU will arrive and i'll test it with this PSU. If this linear PSU will not help I think unfortunately will have to go back to caps on Muratas..
And probably will xperiment with different caps values as 220uF did not removed the hiss completely.