Help with Marantz 2216B caps replace old polar with non-polar caps?

A friend bought a Marantz 2216B amp, i am helping him bring it back to life. The tuner section works fine, so there is hope.
I am looking at the schematic for the phono amp here:

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As i read it C415/16 are the input caps, 1uF @ 50V polar electrolytic.
Can they be replaced by a non-polar cap? The same would apply, i think, to C401/02.
I am curious if this was a design decision, or a design restraint due to capacitor technology and cost at the time.
 

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In my experience, if ANY of those Marantz amps or receivers have ANY of those small YELLOW wrapped electolytics in them - yank them OUT and replace them with a new electrolytic of the same "uF" value.
They are prone to leaking and troubles.
But you need not believe me, I've only got 45+ years in the audio/video service business.
 
Agree w PRR. Polarized caps are meant to have a bias voltage. I think you’d be hard presssed to hear any difference between a good electrolytic and a film cap. The load is 47k so there isn’t much current flowing thru that output cap.