For long time, many have promoted the classic audiophile "hack" to combine tube sound with greater power & slam via a tube preamp paired to SS power amp. However, there are caveats to this approach!
- Impedance mismatch is much more likely here than with the reverse (SS pre into tube power). Some tube preamps will start to perform very poorly into tough loads.
- Tube preamps can sometimes have too much gain, or otherwise prove problematic for noise & microphonics (usually because of the high gain)
- Tube preamp designs often choose poor tubes for the job - e.g. 12AX7, 12AU7 - ugh.
- If you have a capacitor coupled tube pre into a DC coupled SS amp, and the caps fail or start to leak DC, it can damage your speakers. With a tube amp, the output transformers can provide good protection to you speakers.
- I feel you really get more of the "tube" sound from a power amp than preamp.
However, if you select carefully - yes a tube pre and SS power can give very good results indeed! But really the primary determinant should be based on the speakers - some prefer either SS amps, or tube amps. Other speakers can thrive with either. Make the amp-speaker determination first, THEN move upstream to preamp choice.
I have personally heard Sopra 3’s sounding great with VAC tube amp & tube preamp btw - nice speakers!