User's Manual

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User’s Guide ADI-2 Pro FS - v 2.5
34.15 Phones Distortion Comparison
34.16 Impedance based Level Meters PH 1-4
The horizontal level meters in various screens of outputs 1 to 4 show the digital level fed to the
DAC. Above 32 Ohms the level meter's display matches the real analog output level (0 dBFS =
+22 dBu). But at 32 Ohms the ADI-2 Pro delivers only +19 dBu, at 16 Ohms +15 dBu to the
phones outputs, because a reasonable current limiting circuit prevents a too high output power
at lower load impedances. When in Hi-Power mode, the highest undistorted value at 16 Ohms
is -7 dB on the level meter. Consequently it should either change its colour to red then, or re-
scale the highest level to -7. Only then the user would be clearly informed which maximum level
can be issued by the device undistorted. As far as we are aware such a feature is not available
in any such device. That will change right now.
As the current limiter of the Extreme Power output stages
operates in finer resolution, its reaction can be evaluated
dynamically and be used as simplified impedance detection.
Which can then be used to re-scale the level meters.
Exactly that happens fully automated within the ADI-2 Pro.
The peak values to the right serve as pre DAC information
and stay unchanged, but the meter's yellow and red areas
get shifted and extended to the left.
With revised volume settings, where the level meter stays below the red area, the user can now
be 100% sure that the ADI-2 Pro operates absolutely free of distortion, even in the most ex-
treme applications.
Notes on functionality
: The re-scaling happens not before the highest undistorted level is ex-
ceeded. The re-scaling stays visible until the phones plug has been removed. An ongoing over-
load situation causes the activation of the Overload warning screen and a disconnection of the
phones output.