Actually 2800 ohms isn't bad- what's important is the output impedance at 20Hz; the 2800 ohm figure was probably at 1000Hz. If the output impedance at 20Hz is greater than the 1000Hz value (which is common unless the preamp does not employ an output coupling capacitor), you will experience less bass impact with the NAD.
This is one of the reasons tubes get docked for bass relative to solid state. But its more a matter of properly matching components than whether tubes can play bass right or not!
This is one of the reasons tubes get docked for bass relative to solid state. But its more a matter of properly matching components than whether tubes can play bass right or not!