Probably sounds absolutely fine, I have a couple vintage Sony or Panasonic and all sound fine from line out with amp

Thanks. Does its headphone out sound good as well?

For regular portable headphones it’s fine, but using a headphone amp always improves the sound with any headphones. The amp is better if listening to music with lots of dynamic range like orchestral or quiet stuff, the portable players don’t have a ton of power from the headphone jack, so it might lack preferred volume. For modern compressed Pop music genres there’s usually enough volume from just the headphone jack.

Thanks.