Does anyone have any experience with the old Heppner 15" speakers from the 60's? I have a cool amp being worked on right now that has one in. The amp is not right due to someone putting the wrong Transformer in it but it is going to be great when it's done. It is a Hilgen from 1967 and it sounds just like old Led Zepp with my Tele. The amp uses 7591a tubes and it wasn't near as loud as it should be. Any suggestions for the old Supro sound for speakers? Jensens?