I am not sure if all AC3s were this way but I have one where the AGC lead is a pigtail out of the Jones plug. In fact there are 3 pigtails - speaker, AGC, and........ I am having a "Rick Perry" here, forget what the third one is for. It seems to me as if the AC3 is a better design, as it doesn't trap transformer heat inside the case. Rick K2XT