John:
Let's reframe the discussion just a bit. The so-called "volume knob" does not actually increase the volume -- it actually turns it down. At full rotation (maximum volume), the volume knob is simply passing along the signal as it enters the pre/pro from the source. Most preamps seem to be at "full gain" at roughly 12:00 on the dial, which means that the rest of the gain setting is largely irrelevant. It is actually better when the volume pot must be turned up to around 3:00 to yield the maximum volume setting, since this range gives you a wider, more discrete range in which to adjust the volume. It sounds like your NAD is simply set to use more of the rotation range of the "volume" knob.
Let's reframe the discussion just a bit. The so-called "volume knob" does not actually increase the volume -- it actually turns it down. At full rotation (maximum volume), the volume knob is simply passing along the signal as it enters the pre/pro from the source. Most preamps seem to be at "full gain" at roughly 12:00 on the dial, which means that the rest of the gain setting is largely irrelevant. It is actually better when the volume pot must be turned up to around 3:00 to yield the maximum volume setting, since this range gives you a wider, more discrete range in which to adjust the volume. It sounds like your NAD is simply set to use more of the rotation range of the "volume" knob.