The only other power supply we support other than the Line 6 PX-2 power supply is the Voodoo Labs Pedal Power 2 Plus. Other than that, there is no other power supply or cable that we will recommend.
I've been having the same problem as you have, you may have the answer already but id like to try and help if not. The DL4 although stating it needs to be AC converts it internally anyway into DC power, seems pointless to me, guess they want to sell their own power supplies, I'd imagine i will be rejected by line 6 for saying this but oh well if i help one person it's way worth it. The diago adapters work perfectly they just bypass all this internal mumbojumbo. The proof of the pudding is that the DL4 can run on batteries, all batteries are DC