User's Manual
36 
User’s Guide ADI-2 DAC v2.2 © RME 
18. Digital Inputs 
Two SPDIF inputs are available, optical via TOSLINK and coaxial via RCA, but only one can be 
used at a time. The currently used SPDIF input can be chosen under I/O - Settings – Source. 
Set to Auto the input with a valid input signal will be chosen automatically. 
The optical input also understands ADAT format, up to 192 kHz, but only channels 1/2 of the 8-
channel signal are available. 
Using a simple cable adapter XLR to RCA, an 
AES/EBU signal can be received too. To achieve 
this, pins 2 and 3 of a female XLR plug are 
connected individually to the two pins of a phono 
plug. The cable shielding is only connected to pin 
1 of the XLR - not to the phono plug. 
19. Analog Outputs 
19.1 General 
The rear RCA and XLR outputs and the front outputs Phones and IEM are fed from the same 
DAC, hence carry the same signal. They all have individual driver stages with different output 
levels, see next chapters for details. 
All outputs feature mute components to suppress power on/off noise, even when power fails 
instead of switching the unit off via the standby button. 
SNR and THD values as well as frequency response are nearly identical on all analog outputs. 
Both phone outputs feature mute function, over-current detection, DC protection, plug detection 
and DSP control, like auto assigning volume, volume ramp up, user interaction at overload 
detection, and low impedance level meter auto scaling. 
19.2 Line Out RCA 
The ADI-2 DAC has two unbalanced analog outputs that can operate with levels up to +15.5 
dBu (+13 dBu with Volume set to +2.5 dB). The short circuit protected, low impedance line 
outputs are available as RCA jacks on the back of the unit. 
To maintain an optimum level for devices connected to the analog outputs and to maximize the 
dynamic range, the ADI-2 DAC internally uses hi-quality electronic switches, which realize a 
hardware based Reference Level selection in steps of 6 dB over a range of 18 dB: -5 dBu, +1 
dBu, +7 dBu and +13 dBu. 
Note
: XLR provides a 6 dB higher output level in all settings, equalling +1 dBu up to +19 dBu. 
For Auto Ref Level see next chapter. 










