if you have a mains powered Amp or active speakers that you'd like to use, then the 4.4mm port is recommended. Its GND pin assures safe operation.Question regarding the 2.5mm vs 4.4mm connectors. The product literature says the 4.4mm balanced connectors are "grounded connected, so it’s more suitable to use with balanced active speakers." So does that mean I shouldn't use the 4.4mm balanced connectors on my IEM and should instead buy another 2.5mm balanced cable for IEM use? What exactly would be the problem if I plugged my IEM into the 4.4mm balanced input?
They say it would work but not how. It may have some internal resistors that increase the amp impedance.
It says it is not short-circuiting so it might(should?) work. It does say it will not work with every device though so compatibility might be a gamble...
How do they go from 2.5 balanced to 3.5 SE ?
This is not possible without shorting L- and R- outputs.
For the 4.4 it is logical as 4.4 is specifically designed for balanced and SE.