Begging your pardon (really, I am trying to be respectful, here) but all these would work, to some (ahem) "level":
LINE out;
Effects Loop Send;
Pre-Amp out (like on a Pignose Model 100);
"Slave" out;
Headphone out (altho 'phone outputs tend to be a bit hot, they are not hot enough to fry anything- it might just sound like crap- turn the volume down on the Orange 15.)