Just like any amp, a pre-amp with low output impedance relative to amp input impedance is best to minimize distortion and for best dynamics. Input impedance of Class D amps run a range similar to others anywhere from 10K ohm to 200Kohm.
For a tube pre-amp 45-60kohm input amp impedance is the minimum. For lower output impedance ss amps, most any amp will likely match well in this regard.
Avoid clipping a all costs and keep noise and distortion to a minimum and audio life in general should be good.
For a tube pre-amp 45-60kohm input amp impedance is the minimum. For lower output impedance ss amps, most any amp will likely match well in this regard.
Avoid clipping a all costs and keep noise and distortion to a minimum and audio life in general should be good.