User's Manual

User’s Guide ADI-2 DAC v2.2 © RME

26. General

The ADI-2 DAC operates in Class Compliant mode (UAC 2.0), a standard that is natively

supported by operating systems like iOS, Mac OS X, Linux and Windows 10 (since 1709). No

proprietary drivers are required, the device will be directly recognized.

The ADI-2 DAC provides iOS devices with the professional I/O connections they lack.

Professional balanced and unbalanced line outputs, two Extreme Power and IEM headphone

outputs that excel with both high and low impedance headphones, extensive gain and level

adjustments, SPDIF input, PCM playback at up to 768 kHz, and DSD playback at up to 11.2

MHz (DSD256).

The ADI-2 DAC does not supply power to the iPad/iPhone. The latest Lightning to USB 3

Camera adapter from Apple includes a Lightning socket to connect the standard Apple power

supply, allowing to charge the i-device while it operates in Class Compliant mode with the ADI-2

DAC.

27. System requirements for iOS Operation

• Any Apple iPad with at least iOS 5 or an iPhone with at least iOS 7

• Apple iPad Camera Connection Kit or Lightning to USB adapter

28. Setup

Connect the USB cable to the Camera Connection Kit/Lightning adapter. Start the i-device and

plug the Kit/adapter into the i-device’s socket. If everything works as expected, the unit will be

used for all audio I/O. Audio playback in iTunes will automatically be performed by the ADI-2

DAC.

Note

: The i-device’s volume control is inactive during USB operation.

29. Notes

In Class Compliant mode the default clock mode is Internal, and iOS typically sets the highest

available sample rate. Any app can change / set the sample rate to a desired value, but not all

apps include a choice to select one. Setting the ADI-2 DAC (and with it the i-device) to slave

mode by selecting the SPDIF input as clock source, the ADI-2 DAC will be synchronized to the

external digital sample rate. With a wrong external sample rate heavy audio noise will occur.

Without an external signal the ADI-2 DAC changes to its internal clock, with the sample rate set

by iOS or the app in use.