User's Manual

User’s Guide ADI-2 Pro FS – v 2.5
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18. Balanced Phones Mode
In balanced operation, two identical power amplifiers are used to drive one side of the phones
each. Compared to normal, grounded operation, the voltage seen by the phone driver/speaker
is doubled. The power sent to it is even quadrupled.
With the comparatively low power required by headphones, and its already powerful Extreme
Power outputs, the balanced phones mode of the ADI-2 Pro has not been optimized for more
power, but more fidelity. See chapter 34.3 for all the details behind the extraordinary Advanced
Balanced mode implemented into the ADI-2 Pro.
In Advanced Balanced mode the ADI-2 Pro’s maximum output level rises to +13 dBu for Hi-
Power Off and +28 dBu for Hi-Power On. The signal to noise ratio rises from 117 dB / 120 dBA
to 120 dB / 123 dBA. See chapter 34.14 for details about the available output power at the
phones outputs.
Balanced Phones mode requires headphones with separate cabling for left and right channel, 2
wires each, 4 wires in total.
Output PH 3/4 becomes the left channel
output, with former left channel as L+ and
former right channel as L−. PH 1/2
becomes the right channel output, with
former left channel as R+ and former right
channel as R−. Gnd of both connectors
stays unconnected.
There exist different solutions on how to
connect balanced phones, but no standard
as such.
The use of a 4-pin XLR male connector on the phones side is quite popular. The diagram to the
right shows how an adapter cable can be used to connect the ADI-2 Pro phones outputs, using
two stereo TRS plugs and one female XLR connector.
See chapter 14.1.3 on how to activate Balanced Phones mode.
Notes
: The Balanced Phones mode temporarily deactivates DSD Direct mode, in case Direct
DSD is set to On (menu then shows (ON) in brackets). The rear analog outputs 1/2 are muted
during balanced phones operation, because they are supplied with the same balanced phones
signal 1/2, which at the rear outputs represents an out-of-phase mono signal.