I just put in a JPS Power AC+ and it seems to be overheating the amp.
Overheating where? At the IEC connection? Connect the JPS pc back to the amp turn on the amp and play some dynamic music at a moderate to loud level.
Occasionally put your fingers around the pc IEC connector and power cord near the connector. If the connector or cord feels warm to hot to the touch then that would indicate a poor connection. A poor connection under load will cause heating and the heat will transfer each way down the wire/s from the bad connection.
A bad connection could be inside the pc IEC connector. Or more likely a bad fit, poor contact surface area and or poor contact pressure, between the pc IEC female connector and amp IEC male connector. Not all IEC connectors are created equal.....