Hi guys, I have a friend who wants to replace 4x811A with 4x572B in an Ameritron amp. I don't think it's a good idea but he insists a lot of hams do it. What do you think? 73 Bert, VE3OBU No virus found in this outgoing message. Checked by AVG. Version: 7.5.519 / Virus Database: 269.22.10/1367 - Release Date: 4/9/2008 7:10 AM