P5-xe, codex, XLR interconnects

as to the cartridge......IMO given a competent chatter free arm the cartridge and speakers ARE the two most important gadgets in the chain. They are the transducers and also have the highest levels of distortion becuase changing one kind of energy into another is messy....( there will be legion who disagree but a systems engineering math based approach will prove em wrong, ...fodder for another thread
so yes you should look at your cartridge anew...
many of us with more disposable income than sense like to switch cartridges between MC, MM and god forbid other variants..or even just muck with loading, etc in a never ending search for our tail ( or the holy grail )
.....me right now, I am happy with my MC

To be fair, I don’t change my cart often. I did change the settings a few times while upgrading to a different cart, a/b comparing a couple different carts, which was a bit of a pain.  I haven’t change the cart in over a year.  It’s not as bad as it sounded, I think most people once they find the cart they like, don’t really change it until the cart wears out.  I do have friends who switch out carts every few months because it a hobby for them to collect different carts.  Considering you listen to mostly digital, i would try the Codex first before buying or trying anything else. 

The Mogami cables are certainly not expensive, but right now, I have no balanced source. I'm not sure what's available for a TT arm that would fit my Music Hall.

@jetson All cartridges made today are a balanced source.
To operate it balanced, you merely change out the tone arm interconnect cable. This is usually pretty easy. If you have a low output moving coil, then you don't need to have an expensive tone arm cable to make it work- simply one that is low capacitance.

We made the first balanced line preamps anywhere- I've been at this a long time. The advantage of course is that the tone arm cable does not color the sound (like I mentioned earlier, that's the whole point of balanced operation). As a result they don't have to be pricey; we sell tone arm cables made from nice connectors and a low capacitance Mogami cable that work with most arms. IMO/IME, interconnect cables are the hidden cost in a single-ended system; if balanced, they really aren't.
Just about any cable manufacturer will be happy to supply a balanced cable for your arm, and the tone arm manufacturer might too (I have a Triplanar which can be ordered with either single-ended or balanced cables; if an arm manufacturer challenges you that cartridges aren't balanced, have them call me 651-690-2246 and I can bring them up to speed).

My experience with the Codex seems to point to the balanced mode also. In my system, when I switched to balanced, noticed a nice improvement in soundstage and air around instruments and vocals. Everything sounded a bit more natural IMO. Using a quality optical cable is a good way to connect to a streamer. This combo bested my Cd player which is a Cambridge 851-C. 

I do agree with tomic (Jim) that going to the Treo CT. would be a good choice if you can swing it money wise. The Treo is like taking a model 2ce sig. ll and upping it to it's highest possible level. Not to mention looking nicer too.

 which source do you listen to more ? work on that one first...

Indeed. I have a P-5xe and a QB-9 but rarely listen to vinyl anymore with 24 bit downloads and Tidal via Roon. Sounds fantastic. To my ears, hi-rez and the QB-9 combine the textures of vinyl with the tomb-quiet backgrounds of digital. That said, I’m saving my pennies for a QX-8.