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

I'm not sure you need to spend $10K. In my opinion the AT7 QS Line Stage gives me definite improvement for my PSAudio DSD. I would never be without it streaming of otherwise.

And let me add some of my findings concerning, at least  PSAudio's built in streamer. Everything sounds better with the Bridge ripped out.

I use Audirvana on a mac mini and USB that into the DSD with a nice cable. I stream from Qobuz. Once I find an album I would hate missing as in when Qobuz removes it, I search for the highest rez I can find and purchase it.

My only point is that the pre is just part of the chain and anything is only as strong as its weakest link.

BTW they are selling factory checked DSD on PSAudio's site for $3K.

@oddiofyl 

"I upgraded to an Aurender N200 to pair with my DAC and feel it was a worth while choice despite it's price tag.  I don't even play CDs anymore "

Whats this....C..D... thing you speak of?

@puffbojie I used to own the Modwright KWA 150SE. I actually had two of them in mono at one point and went back down to one. 

Yes, a preamp will do wonders for you, especially if streaming Tidal or Spotify. IMO the Modwright LS-36.5 DM is one of the best preamps, especially maxxed out with good tubes. When I had mine, I started without the DM, so it was just the single chassis. That already was leaps and bounds better than Dan’s SWL 9.0 SE. the DM upgrade was yet another league higher.

I no longer own Modwright gear but have always been a fan.

The NAD C658 is not that bad of a DAC, especially due to its DIRAC features. Otherwise it by itself is still a clean DAC. While I like BluOS, you also will get much better quality from digital files by having a dedicated streamer. I am partial to Aurender and became an Aurender dealer because of my positive experiences with them over other brands, but there are a lot to choose from. 

I’m fairly certain with your system, you will get greater sonic gain by investing in a good preamp first and streamer second. 

Nobody has brought it up, but quality power will also be a huge contributor in advancing your system’s sonic performance. The KWA 150 SE is a high current amplifier and will benefit from a quality conditioner and aftermarket power cable. 

I am also a preamp first audio fan. brings everything to life.   yes.  

don't underestimate the quality of your streams.