Just using one of the inputs on the EP125 will work fine. From your manual --
"...connect a single shielded cable from the receiver’s “Sub Out” jack to the “Left” or “Right” “Line Level In” RCA jack on the Epicenter’s rear panel. There is no advantage to using a Y-adapter because it is a mono subwoofer signal from the A/V receiver."
I have heard that using a Y connector will increase the input to the sub by 3 to 6 dB. If true, that might be a minor advantage, but I can't attest to the validity of that statement.
