Dear @teo_audio : Rigth you are and changing the old filter caps for new ones makes a true quality improvemnt in what we listen it.
I just made the electrolytic screw type filter caps ( 70k uf each side. ) in the power supply of my ML very old ( 35+ ) 20.6 monoblocks and the improved quality level is something totally unexpected by me because I only made that change to stay " calm " because the amplifiers were working just fine.
Regards and enjoy the MUSIC NOT DISTORTIONS,
R.