OIL CAPACITOR MEASUREMENT

Oil capacitor is known for smooth sounding (and big and heavy). Their change of phase is smooth over wide frequency range.

​All measurements were taken on same test equipment. Result may vary with different test condition.
Aerovox 0.5uF 0.5uF 100Vdc:
-90 to -80 degree phase response up to 30KHz
irregular response between 500Hz to 1000Hz. (below macro view)

Audio Note Copper Foil PIO 0.47uF 630Vdc:
-90 to -88 degree phase response up to 220KHz
Phase response is not flat, but the change is smooth.
irregular response between 300Hz to 100KHz. (below macro view)
Micamold 8uF 1000Vdc:
smooth phase response up to 100KHz
irregular response between 200Hz to 400Hz and 1KHz. (below macro view)
Micamold 10uF 600Vdc:
smooth phase response and crossing 0 degree at 600KHz (no longer acting as a capacitor)
irregular response between 200Hz to 400Hz and 1KHz. (below macro view)
Sprague 10uF 600Vdc:
smooth phase response and crossing 0 degree at 160KHz (no longer acting as a capacitor)
irregular response at 900Hz. (below macro view)
Sangamo 10uF 600Vdc:
smooth phase response and crossing 0 degree at 230KHz (no longer acting as a capacitor)
change of the phase is smooth (below macro view)
Western Electric D161270 1uF 200Vdc:
smooth phase response and crossing 0 degree at 450KHz (no longer acting as a capacitor)
irregular response below 1KHz and at 4KHz. (below macro view)