Why is my expensive streamer to my DAC better than sending Roon or my Mac directly to DAC

You can probably achieve similar result with Mac via DDC reclocker/isolator, i.e. Mac => DDC => DAC. Also, may need to adjust OS to make sure fewer processes running putting less load on CPU and fewer interrupts. After all, streamer IS a computer.

Streamer is a dedicated computer with fewer things running and less performance hardware, so less noise. Tuned for the purpose rather than for general tasks.

The streamer is getting the initial signal from the noisy computer

weiserb

The streamer is getting the initial signal from the noisy computer

You'll probably get a better result by connecting your streamer via ethernet to its own port on your router.

When you connect a PC directly to the DAC you are opening up a pathway for PC noise to get into the DAC. Not good.

Your Lumin isolates that network noise and sends a clean signal to the DAC. A PC added to network can also add noise to the network. Think also of all the other things connected to a network, printers, computers, security cams, etc.. All of this can add noise to a network.

I think the new Lumin U1-X has a fibre optical connection. My old Lumin X1 had a fibre connection. A fibre cable is made out of glass and glass cannot carry the noise that I described above. Fibre is better than RJ45 Ethernet connection for the same reason.

I use a cheap very internally noisy computer as my ROON CORE server. The way I have it setup with fibre optic cables makes my system sound great in 3 rooms of the house. My $500 ROON CORE server is actually residing under a bed in my guest room, nowhere near my audio systems.

weiserb the streamer is often getting its signal from a streaming site TIDAL OR QUOBUZ rather then a pc