please advise.. ext. LPF summing differential outputs by an opamp

[ASSaBeong]

Hi

Please some advice...

pc soundcard -- AK4395 DAC board -- headphone amp -- headphone.

I want to modify analog low pass filter section connected to AK4395 DAC's output.

change opamp(2134 --> ad8620,opa627,lt1115,ad797,ad843...)
opa 2134 is operating as an analog low pass filter summing the 4395's differential outputs.

change power supply bypass caps
(general purpose 85' AL --> 105' low impedance AL cap)
(0.1uf mks --> 0.1uf mkp)

change the film cap, determining the cut frequency slope??
(2.2nF mks --> 2.2nF fkp, mkp or silver mica)

change output coupling cap??
( 47uF 85' general purpose AL, SMD type, --> ?? suggest!!! )

Please some advice.

Thank You.

analog part circuit is attached.