There's one on Ebay at https://www.ebay.com/itm/Kahn-Research-Labs-CV-1982-TSC-26-SSB-Converter-for-R-390-RARE/193578225523?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649 Is anyone familiar with it? Tube complement? thanks, Phil W5BVB