Lost definition with the stereo out fader below the Zero db

With Cubase 7 i can live at zero the stereo out fader and with the Level Signal fader i can listen at the desire volume.
But i read around the web that put down the fader under the zero level (on the stereo out buss) i loss definition.
It is true?
I ask this because the PRO SE advice to buy an Analog Volume Knob for down the volume and not reccomended to push down the fader in the digital domain.

No. Completely false.

A friend of mine (PRO Sound Einginerr) tell me that when with a measurement match the:

  • output level with Analog knowb volume (On cubase set to zero dbfs)
  • and output the level with fader turn down below the zero
    The first sound better .
    However here there is a explaination in the SPL website about VOLUME 2 (a big knob analog volume…)
    Who needs analog level control?

Simply put—most DAW (Digital Audio Workstation) users. A majority of D/A converters and sound cards provide nothing in the way of analog level monitoring control, and this means the necessity of varying signal levels at the converter outputs. The result is a lowered bit rate in the monitoring signal, which can lead to commensurate loss of audio quality.
A further, very interesting application area is in the construction of a straight, audiophile-quality stereo playback chain, where the Volume2 is situated between the playback machine and either power amp and speakers or simply active speaker system. In such cases, the playback machine must offer analog outputs. This provides for minimal financial and electronic efforts through the most direct possible playback path.
Common AV receivers employ VCA and DAC components which tend to produce more distortions, or the signal runs through further AD/DA converters for the volume control. Thus especially with SACD or DVD-A sources, only a high-quality analog, direct control of the source output ensures an unimpaired playback of the original information.