Just picked one up. It's a combo EL34 version with a tube rectifier so this means its pre 1970 right?. Whomever had it before me swapped the 15 inch speaker for a newish cheaper Goldwood 15 made in China but it has a made in Holland Amperex 12ax7 and the rectifier is an old RCA. The power tubes are Sovtek 6L6GWC instead of EL34. I don't think any mods have been made for the tube change. I want to get a 3 prong power cord put on it and have the amp guy look it over and check everything out. Is there anything else I should know? I did read the forum here last night and got some info. The 7199 is an old Sylvania. Is the amp running at 8 ohms or? The transformer say sunn and the other one says Dynaco