Question about tuning a FA3ES phonostage

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Im not sure if im right here,but i need some advice...
I own a old Sony TA-FA3ES integrated amp which sounds decent with CD
as source but sucks via Phono MC (with a Dynavector DV23 RS MK.2).
I made a little websearch and learned that the phonoeqpart consists
of an input stage with two 2SC2545 and a RC4560D Opamp. I also learned that
later models (for example the FA30ES) use the same circuit diagram but
with a NJM2068DD Opamp.
My question is would it be worth while to change the Opamp to NJM2068DD
or an probably better Opamp like LME 49720 in my amp? What other options do i have to better the sound of the give phonoamp ?