Hi Rob, Actually, in terms of the potential reduction in transmitted system IMD (when using SSB), I do not believe that Class A operation of the exciter is worth the risk involved. http://www.qsl.net/ab4oj/icom/ic756pro_notes.html#imd Cheers for now, 73, Adam VA7OJ/AB4OJ Scanned for viruses by Blue Coat http://www.WinProxy.com/