The recommended amplifiers for the JBL JRX 125 should have an output of 500 W at 4 ohms minimum. The maximum output should be no more than 1,000 W at 4 ohms.
Due to the high output of the JBL JRX 125 speakers, the right power amplifier should have a protect mode. This mode prevents the amplifier from blowing a fuse if consistently operating at high levels. It will also prevent you from repairing or replacing damaged parts of the amplifier.
JBL JRX 125s can be connected in pairs or as single units. Therefore, it is a good idea to get a power amplifier that can be operated in mono and stereo modes. They should also have built-in cooling systems to prevent overheating from extensive use.