I just bought Sunn 1 x 15 cab. It doesn't have a back plate on it, but has a very clean logo plate that looks like it's from the 60's. It looks as tall as a 2 x 15 cab, but only has a single 15. Does anyone have any idea which amp this would've been paired with back in the day or what the original speaker would've been? (Picture forthcoming). I'm using it with my 2000s for now and it sounds nice even though the original speaker was replaced with an EV.