Ampli JVC e Gm Volume...

Stavo curiosando qui:
http://pro.jvc.com/prof/attributes/tech_desc.jsp?model_id=MDL100386&feature_id=02

Le note tecniche si riferiscono al seguente ampli "pro":
http://i107.photobucket.com/albums/m283/bowtie427ss/JVCA-X901.jpg

A parte la solita corrente di bias variabile dinamicamente, per ridurre la distorsione di incrocio (Dynamic Super-A, mi sembra analoga alla Technics New Class A), mi ha colpito il modo in cui viene gestito il guadagno (volume):

"Gm Volume

A typical digital program offers a signal-to-noise ratio of more
than 90dB, or a dynamic approaching 100dB. It's true that there
are a large number of amplifiers that clear the 90dB hurdle.
But in real-life performance, few amplifiers are able to maintain
the ratio at such a high level under all conditions: the ratio tends to
shrink as the volume is reduced from maximum to more
usual listening levels, because residual noise remains constant.
The culprit is the volume control, that is, a variable resistor
(potentiometer). It changes the signal-to-noise ratio depending
on its setting. The ratio is highest only at its maximum; at
other settings - including those most frequently used - the ratio
is poorer.

Gm Volume has the ability to amplify signals and adjust their levels
from minimum to maximum. It lets you enjoy the highest
signal-to-noise ratio at the maximum setting. Yet at other
settings it actually reduces noise as the volume is reduced.
Since Gm Volume allows the amplifier to deliver always optimum
gain, it provides a signal-to-noise ratio that is about 25dB
better than that provided by norma volume control designs.
Moreover, the volume control itself is not in the signal path,
therefore sound quality cannot be degraded by distortion and
crosstalk caused by poor mechanical contact resulting from
corrosion."

Se il potenziometro non è in mezzo al percorso del segnale, immagino che questo non venga mai attenuato ma si vada a modificare direttamente il guadagno interno dell'amplificatore, come sui pre Technics con VGCA (Variable Gain Control Amplifier).
E' così? Mi sembra molto interessante come soluzione.

Stesso sistema ho visto che è presente pure sull'AX-1100:
http://www.jeff-young-design.com/JVC/amps-tuners/AX-1100.jpg

Cosa ne pensate?
Possibilmente cercando di non condannarlo aprioristicamente a morte soltanto perchè è giapponese, e di valutarne il profilo tecnico ;)