RME Audio ADI-2 Pro User Manual page 67

This design, as common as it is, has several disadvantages:
•
an analog inverter stage has to be added to the signal path
•
the common mode situation of the signal at the phones is compromised by the difference
between + and – phase, caused by the analog inverter
•
multiple relays and laborious cabling with wires running back and forth from/to the PCB are
typical for such a design
The ADI-2 Pro deserves a different, better way to go balanced. The picture below shows RME's
exclusive design as implemented in the ADI-2 Pro.
The ADI-2 Pro has two DACs and a powerful DSP. These ingredients allow for a much im-
proved version with several advantages:
•
The whole path from DAC to phones stays totally unchanged. Not a single relay or change
in cabling is necessary within the ADI-2 Pro.
•
The whole signal path from DAC to the headphone speaker is balanced (!)
•
Signal inversion happens fully transparent and lossless within the digital domain
•
As known from mono-summing with ADCs and DACs, the two channels of each DAC now
operate in that way. The signal to noise ratio rises by 3 dB.
•
Indeed the whole analog output chain is part of that mono-summing. Noise from the Gain
amp and the driver stages is identically reduced.
•
The same is true for THD, which is not only lowered by the smaller output voltages per
amp, but also by the common mode suppression that the phones' speaker realizes. Fur-
thermore small deviations in the DA output path's hardware are further minimized by aver-
aging.
User's Guide ADI-2 Pro © RME
67