Interesting Sid, Axiom audio says there is no problem daisy chaining their subs togethor. I have 2 ep350v3's and 1 ep600 daisy chained to my Denon 2805 and it works fine. When comparing the SPL readings Daisy Chained versus individual lines using an adapter, I didn't notice any difference in level reductio or SPL. Electrons really don't notice any difference do they?
Anyway, here is another option I've used with success from partsexpress.