If you intend on putting the ox stomp in the effects loop of the HX stomp then you need the Y cord. You could just run from output of HX => Ox Stomp wtih seperate cables for left and right but you won't be able to insert any post cab effects.
If you intend on putting the ox stomp in the effects loop of the HX stomp then you need the Y cord. You could just run from output of HX => Ox Stomp with separate cables for left and right but you won't be able to insert any post-cab effects.