Akanrg- Here's the scoop on Winged 'C' tubes: (http://www.tubesandmore.com/scripts/foxweb.dll/catalog@d:/dfs/elevclients/cemirror/ELEVATOR.FXP?PAGE=SUBCAT&SEARCH_TREE01=01_TUBES&SEARCH_TREE02=00003_WINGEDC) It's good to know what iteration of a particular tube you have from them(when it was manufactured), as there have been swings in quality over the years. I'm using the latest version of the =C= 6550's and can't be happier(WELL- maybe with a matched octet of NOS TungSols.....).
