SACD Player Mods vs. Outboard D/A converter?

A used Bel Canto DAC may be cheaper than modding your C555es. I don't have personal experience with the Bel Canto units, but they have been highly reviewed. Check 6moons.com and Soundtage.com for Bel Canto DAC reviews. I do own a Modwrighted NS999ES DVD player and it's excellent. I don't believe Dan wright does mods to the C555es, but you should check with him to be certain. Richard Kern may be your best bet for Sony mods.

Get a Chord DAC 64 and any transport jumps levels in musical presentation. I have one and use an Electrocompaniet, a Pioneer 300 disc changer, and a Sony 333 changer as transports. All sound great through it with no mods.

Get a Marantz.

Keep in mind, going the mod route saves you the added expense and anxiety of a digital cable and a second power cord. (Anxiety because you have to worry about whether you have made the best choices. Some of us like the angst, though.)

My impression is that most of the mods are strictly parts upgrades. This raises a fundamental question in my mind: What is the relative importance of parts quality vs. circuit design? Of course they both matter, but what I am asking is, can you take the basic Sony (or other brand) circuitry and get near state-of-the-art performance merely by upgrading the parts? Or is a different circuit design needed? If I had any engineering background, I might have an informed opinion on this question.

According to Paul Bui who own the sony dvp 9000es,
the tube output and dac upgrade made a whole lot a
diferrence, I send mind to Dan sony 9000es, for
The Reference Mod. I trust him.If you go to
harmonicdiscord.com So many posted there about
mod. You can read the positive feedback
from R Kern and D Wright.
GOOD LUCK