You could go parallel feed with cap iso and a split choke and see if it works, keep most of the original sound. An Edcor transformer may work fine as an inductor to feed DC. I've saved a couple of DC coupled output transformer situations this way. The partial failure in the cases I've seen is that the winding is going just enough that it doesn't like current draw over a certain amount, but still measures fine for audio signature and DC resistance.
Don't know how specialized your pair is, but I'd be more inclined to fix the one, sell it, get another to match the good one.