ETSlan PA-813
S/PDIF signal is almost identical to AES/EBU
key differences:
AES/EBU is usually Balanced vs. S/PDIF Unbalanced, some "professional" video equipment has unbalanced AES/EBU like Matrox MXO2 Rack for example but its rare, usually is Balanced.
AES/EBU impedance is 110ohms,
DMX is 120ohms
S/PDIF is 75ohms.
that can create signal reflection problems "cancelations" at some points of the cable.
AES/EBU usually is 5v, S/PDIF is 0.5v
the ETSlan.com PA-813 are a small balun "transformer" and also H-Pad -10dB.
they work well, but if you replace the ground wire with a better AWG24 from Proel or Belden would work better.
also needs a BNC to RCA adapter... the BNC connector wears and gets loose over time, needs to squeeze the gold pins closer again, if you have intermittent signal...
the other brands ive tested are Not as good, canare, neutrik, etc....
Trnansformer is the way to go...
with litz wire, or single strand very small AWG between 30 & 40.
the coil is 1cm donnut with 0.25cm ~ 0.5ccm core
very tiny donnut,
turns are also very small, like 5, less than 10.
3x resistors,
1 ground AWG24 wire, done.