Should I upgrade to XLR interconnects?

Get some Mogami xlr's from guitar center and check out the sound. I doubt any benefit to be had. Much gear with xlr inputs then converts to single ended. It depends if the gear is truly balanced
Alan

I checked your integrated. It is not a balanced design. It is single ended and probably will not benefit from xlr cables. Stick with what you have
Alan

No brainer. XLR should be equivalent sounding but in addition XLR negates a whole host of ground loop and other issues - so performance will always be at least as good but can often be better in many instances.

What RCA style interconnects are you using?  Both you amp and SACD player are fully balanced designs and are intended to be linked via the balanced (XLR) input/outputs.  Whether or not you will hear a meaningful sonic improvement is a question that only you can answer after trying and comparing both.  There are retailers that lend cables for you to evaluate.  Going that path will minimize the initial financial impact of comparing.

The devil is in the details here. Manufacturers call XLR inputs "balanced" in their literature, whether or not the circuitry design is truly differentially balanced or not.

If your gear is not differentially balanced, it probably uses an opamp in the input/output stage of the XLR circuit which is almost always detrimental to sound quality, and many times significantly so.

If your gear is differentially balanced, then using XLR cables is advantageous, not only because it cancels incoming noise from upstream, but usually provides +6db of additional gain.

Marantz states "Line level inputs feature unbalanced (RCA) and fully balanced XLR options for maximum connection flexibility." in the literature of the PM-11S3. The use of the word, "fully" should mean that it is differentially balanced. Their literature for the SA-11S3 states, "The sophisticated fully differential analog output stages feature our exclusive HDAM SA2 and HDAM technologies,"

I would recommend using XLR cabling in this case. Whether the sonic differences are significant to you and worth the investment will only be known after some experimentation.

Dave