The front and rear panels diverge according to purpose. The M400 is intended primarily as a premium DAC/Pre (no headfi) with extensive digital inputs and a choice of fully balanced and unbalanced outputs. The Dp5 changes priorities as a music player, prioritizing access to digital file storage via wired and wireless inputs and a wider range of digital and analog outputs.
The front of the M400 is quite Spartan with a small color LCD display on the left and a multi-function dial with center push button on the right for volume control, menu selection and power. An LED at the center of the knob marks power status with red for off, green for power up/down and blue for on. The rear panel has ample connectivity, featuring the regular complement of coax and optical alongside USB B and I²S over HDMI as well as a Bluetooth antenna. Outputs are on fully balanced XLR then RCA.
The Dp5's more complex abilities demand more functional control. The front panel sports a large 3.5" IPS LCD screen on the left whose display manages a wide range of information from menu functions and volume level to cover art by name and technical overlay. The center has 5 function buttons for play/pause, track skip/fast-forward, track back/rewind, power and display and a back control for menu navigation. Additionally there's a ¼" headphone jack with dedicated driver stage. On the far right sits the M400's multi-function dial to manage menu access and volume but power on/off relocates to another button.
The rear panel of the Dp5 reflects the functional balance of source component. Conventional inputs are reduced to a pair of USB 2.0 ports for storage media up to 4GB. For internal storage there's a micro SD card slot. Modern sources get the nod with 2.4/5G WiFi for NAS access and other network sources backed by hardwired LAN as well as Bluetooth APT-X.