TEchnically, most any SS pre-amp should match well with most any SS amp including Class D. So that is not a factor to be concerned about when choosing a SS pre-amp to use with Class D.
Where it becomes an issue is with tube pre-amps that typically have higher output impedance. Not all SS or Class D amps have high enough input impedance to work optimally with a tube pre-amp. Somewhat muddled sound, not clear and articulate is often the result.
I have Bel Canto ref1000m amps with Arc sp16 tube pre-amp in my main system. I also have Bel Canto c5i integrated amp in another....no tubes there, all digital, only thing needed is an external streamer. Amps are similar but sound is much different mostly tonally which I would attribute mostly to the difference between the pre-amps used with each and the DAC also to some extent. The best description of the c5i no tube sound is more electrostat like....more airy and neutral perhaps and also very clean...dead silent. THe tube preamp combo is very similar but the ARC pre-amp adds a touch of midrange warmth and sparkle. Which is better would come down to largely a matter of preference. I am strongly considering getting away from tubes altogether when the time comes to replace the ARC sp 16. Something like the new Benchmark pre-amp has a lot of appeal to me.... also dead quiet and adding nothing much of its own by all accounts so far. Plus I Iike Benchmark’s no nonsense, R&D based approach to product design in general. Also can’t go wrong with Bel Canto in my mind. But the Audio Research tube pre-amp does sound really good......
Where it becomes an issue is with tube pre-amps that typically have higher output impedance. Not all SS or Class D amps have high enough input impedance to work optimally with a tube pre-amp. Somewhat muddled sound, not clear and articulate is often the result.
I have Bel Canto ref1000m amps with Arc sp16 tube pre-amp in my main system. I also have Bel Canto c5i integrated amp in another....no tubes there, all digital, only thing needed is an external streamer. Amps are similar but sound is much different mostly tonally which I would attribute mostly to the difference between the pre-amps used with each and the DAC also to some extent. The best description of the c5i no tube sound is more electrostat like....more airy and neutral perhaps and also very clean...dead silent. THe tube preamp combo is very similar but the ARC pre-amp adds a touch of midrange warmth and sparkle. Which is better would come down to largely a matter of preference. I am strongly considering getting away from tubes altogether when the time comes to replace the ARC sp 16. Something like the new Benchmark pre-amp has a lot of appeal to me.... also dead quiet and adding nothing much of its own by all accounts so far. Plus I Iike Benchmark’s no nonsense, R&D based approach to product design in general. Also can’t go wrong with Bel Canto in my mind. But the Audio Research tube pre-amp does sound really good......