[DaleHCook]

But opt on the H-13 are. That's been about a 50/50.

That is good to know. I hope the OP can find a UOT for a reasonable price - major brand NOS 10 watters are selling for $50 and up on the auction site. At those prices he might be better off buying a Hammond P-T125D from Antique Radio Supply at $55.35.

A word to the wise - some sellers on the auction site are listing 70.7 and 25 volt line transformers as UOTs. It pays to have lots of old electronic parts catalogs to look up part numbers and see what a part really is.