Q: How come my DL4 pedal says “9V AC” for Power Requirements, but the DC-DL4’s output is rated 12V DC?
A: The DL4 was originally designed to be battery powered, or to optionally be powered by the Line 6 PX-2G power supply (which was a 9V AC output). Due to Level VI power supply efficiency requirements in North America, the PX-2G was discontinued in North America.
However, the DL4, as well as the DM4, MM4, FM4 and AM4 stompboxes, can also work with a center-positive 12V DC supply, such as the DC-DL4 power supply.