The Amdek AMDC II is the "big brother" of the AMDC I, a system with two 3-inch drives in a single case. Released in 1983, it was intended for Atari users who needed significant disk storage expansion. The device provided access to a total of 360 KB of data (180 KB per drive/side). The case was wider to accommodate two Hitachi mechanisms. Its size now more closely resembled a classic floppy disk drive, but it remained shorter than the Atari 810. Each drive had its own "Eject" button and its own set of activity indicators.

The AMDC II was even more expensive than the AMDC I. Due to its high price and the exotic nature of 3-inch drives, it sold in very small quantities. Today, finding a working AMDC II is a collector's prize, as spare Hitachi 3-inch drives are extremely scarce.