Are higher end preamps worth the investment when you are only streaming Tidal & Spotify ?

@lalitk yep, Dan’s equipment is awesome and a great value but am in the used market unfortunately. I am keeping an eye out for his stuff. @ vonhelmholtz yeah that NAD C658 DAC Streamer is really a weak link but the DIRAC feature really helps with my room. I might have to get a stand-alone room correction device in order to update the streamer and Dac as the NAD does not allow you to disengage the DAC from what I understand.

Qobuz (best) and Tidal can sound as good as CDs, stored files or vinyl given the right system. The sound you get is really dependent on all your components. 
 

Your system is a sum of its parts. I have found that with careful choices topically an optimal system will have all components with roughly similar investments… so streamer = DAC = Preamp = amp.

That said, if I were going to invest more in something it would typically be the preamp. It really is pivotal in setting up the sound. 

With the goal of achieving higher fidelity, would a 10k -12k MSRP preamplifier be overkill when you only stream from Tidal or Spotify?

Yes, the C658 is fine for your current setup. If you want an upgrade measure your room's FR and post it in your profile and we can discuss. Acoustics are #1.

A preamp will bring life to your system.

Don't believe me, ask Paul McGowan.

Bob

Tidal and Qobuz on a great streamer and DAC sound better than most CDs because most CDs are played on a CD player with internal DAC.

Now if you’re doing CD right, with a good CD transport to your same DAC, they are likely hard to tell apart.

Jerry