Why does my old CD player sound so much better than my new streamer?

It is the different DACs which is contributing most of  the difference in sound you hear.
  
I have a high end CD player with a digital USB input to allow a network bridge (streamer with no DAC) to run through the same DAC.   Initially CD sounded better. However by making the following adjustments to the streamer they now sound virtually identical:
1. Connect the streamer to the router via Ethernet not WiFi 
2. Turn off in the streamer the following: Bluetooth, WiFi, HDMI, and any other connecting methods other than Ethernet 
3. Introduce a good quality network switch (eg Cisco) between the router and the streamer 
4. Use Cat8 Ethernet cable. 
5. Try different USB cables. This provided subtle improvements. 

After these changes the sound is almost identical. 

A high quality dac ,like the new Lampizator amber 3 
which is $2750 is a vacuum tube dac and night and day better then Any 
streamer with built in dac is you want a you are there 3D perspective 
enjoy the music .com just gave it a rave musicality 5 stars across the board.
a good outboard dac and good usb  cable , you are all set. Here is no point 
buying a better streaming dac even their $10k LUMIN will not touch the new Lampi Amber 3 thst I can assure you having a great designed dac and then add several Vacuum tubes to the mix even streaming will give you a much warmer 
real perspective ,even less then ideal recordings are listenable ,and a 
2 week return policy if not happy. I sold my PS Audio dac That was $6k
to buy this Amber 3 it is thst good,  and can make it better still with a premium fuse and great vintage tubes ,from Brent Jesse recording ,or Andy at Vintage tube services.

Why would you want to pay a lot of money to tweek the sound to be warm and easy-listening and boring? Yes, if you like to listen to bad recordings but otherwise?

all this banter.... here’s a simple answer ready for it? Ready , ready , ready here it comes ready, ready , ready , ready................................................IT"S CALLED NOISE..... that’s why your cd player sounds better. I’m not 100% sure or your setup but to get it to sound better.
A. Eliminate noise where possible and if your budget can afford it. A Sotm switch will do that for you (has a built in clock)
B. If you use ethernet in your system Sotm Cat7 cables filters will also assist.
C. Word clock if you can afford it
I’ve heard these on streamers and the difference is night and day no exaggeration. The biggest leap when the switch was added...

Problem solved.......

You might prefer the Lampizator amber 3 to the PS Audio DS dac because it’s tube based and you like the sound of tubes. That’s cool. But, If you compare the 2 dacs, technically the DS is in a different league, and sound wise, it’s an excellent sounding dac. A lot of the time, when people originally listened to the DS dac, they were listening with an older firmware release. I just upgraded the firmware on my DS sr yesterday and got a bump in SQ for free, try that with most other dacs at any price, you can’t. Also, there are a few ways to setup the DS to get the max SQ out of it, these tips are on the web.
Looking at the Lampizator amber 3, where is the Ethernet port? I don’t see on their website that it’s FPGA based, so no future upgrades, I don’t see that it’s a Roon endpoint? Is there MQA or DSD support?With most streamers and dacs, you are using the USB interface which is flawed from the start. Salesman and tweakers are going to try and sell you technology to make USB sound better and some do like using the best cable and reclockers, but IMO it’s like putting lipstick on a pig, it’s still a pig.