Well today I finally was mounting some Pioneer newly produced heads on a Teac A series machine. The problem encountered is that they may work if a transition plate can be installed. The heads of the Pioneer type have mount screws too far forward while the Teac screws are mounted back. In this the Pioneer head will not present enough penetration to contact the tape. I have contacted some people about a correction plate to see if this is a possibility. Just thought some other Technicians or Teac deck owners would like to know.