The pre out voltage of the Alpine iLX-W650 is 4V. This means that it has a good amount of power to drive speakers, giving you excellent sound quality and volume control options. The pre out also allows for external amplifiers to be connected so you can easily increase the overall output if desired. With this great feature in combination with the other features like Apple CarPlay compatibility and advanced touchscreen display, the iLX-W650 from Alpine makes an excellent choice for anyone looking for a premium car audio system.