Hi Luca, great to hear from you and to know that you enjoy those UPOCC 4x4 XLR’s. They “are” incredible balanced IC’s.
Your project sounds exciting and like many things audiophile, “expensive.” 
1st question is answered by Galen.
"ICs, Especially XLR, are designed to go long runs. Cable +I/O and the expected cable high impedance load. Speaker cable not so much.
The reactance does change, but yes, get the length reasonable and results are benign. Curiously, the basic “character” of a cable is consistent to length as the ratio of all the aspects that give it a sound are constant.
How does that work? At RF (it’s easy there) Impedance is a VECTOR (fancy word for ratio) of the real to imaginary parts of the signal. The equation is SQRT (L/C). As the length goes up, the ratio stays the same as L and C follow along with the length. Using basic number 2/4 = 4/8 = 8/16 and so forth. At true RF, the termination can be a PURE RESISTOR. Why? Because the equation assumes we are at true stable transmission line frequencies where SQRT(L/C) is the impedance. Since L and C are opposite degree phase the “angle” of the vector is math wise a pure number because the two phases cancel. Presto, theory says it is a pure resistance at RF thus we can terminate into a resistor.
The Return Loss, RL, is the mismatch to the load AND the remainder of the vector’s reactive value BELOW where the cable is a pure resistance or…the wrong resistive value compared to the resistor used as a load. Some call that resistive and vector mis-match SRL or the STRUCTURE of the cable missed the intended vector magnitude. Some devices have a variable load you can tune for the lowest reflections based on the cable’s true structure (impedance). You can cheat and test SRL, when you and I are stuck with true RL as our stuff is a set ideal 75-ohm resistance (that could be off too!). We can’t remove a 73-ohm’s cable SRL to a 75-ohm load.
Audio cables are NOT even close to RF and reactance properties and phase shift are always there through audio. How do we know that? Like Vp through audio, the phase for L and C go from zero at RF to a maximum value at DC where it looks capacitive. And again, this happens right through the audio band. All passive cable does this. ALL of them. Just look at an open-short impedance + Phase trace.
But RF’s impedance equation explains HOW a cable retains and impedance no matter the length. It also rats out more of analog’s problems.
We want to improve the WORST thing in our systems. With a turntable, moving the table away from noise significantly improves the clarity of the sound over anything the cable can offset. Thus, moving the table is better than longer cables and where ever that is, may not be off to the side, is where the table really wants to be.
Want proof? Set your needle on a STILL record. YELL at the cartridge / head shell and listen to your voice come out the speakers. The vibration moves the needle and how it all works. The music is playing more than once in a room with the playback speakers. This smears the sound. No cable can be better than removing that as an upgrade.
XLR can go 100 feet per the specs and some even 200 feet. 30 feet is pretty easy for a good XLR cable.
Best,
Galen"
The 2nd question is for me… “Everyone knows” that we don’t discount cables. We didn’t build in price margins for dealers and use the same basic cost/pricing matrix as BJC keeping costs as low as we can and to make Iconoclast cables within reach to as many audiophiles as we can. We can by helping with trades as shown below. Private emails are always best.
The 3rd question is also for me… I will take a trade where a 5.5’ “Gen 2 XLR” cable is traded for a “Gen 2 XLR” +/-26’ cable assuming they are in good shape.
Have a great weekend.
Bob
