I have a Head Phone amp and a DAC. Im connecting to a new Roon Nucleus with my sub services and my ripped to storage tracks. Do I still need a "Streamer" component? I access Roon on my Mac. Or does Roon NUC handle the streaming?
Describe your network setup
Cable modem, into a good network switch into Nucleus on a 2GB speed service.
You can quite happliy use your DAC/Headphone amp connected to your MAC with your Roon Nucleus. You just need to run the Roon application (not Roon Server - you only need one Roon Server and that is provided by the Nucleus) and then the DAC connected to the Mac will be visible to the Roon system. However, the Mac hosted Roon endpoint will only be useable when the Roon application is running.
Alternatively, you can install and run Roon Bridge on your MAC which provides the Roon Endpoint functionality in the same way as the Roon application but does not provide a UI. Roon Bridge can be configured to launch whenever your Mac is turned on - which makes the endpoint(s) provided potentially visible to other Roon controllers even when Roon is not running on the Mac.
If you didn’t want to use your Mac for any reason, then there are a number of alternatives:
Assuming your DAC supports USB Audio Class 2 and can be located close enough to the Nucleus, you can just connect it to the Nucleus using USB.
If your DAC does not support USB audio, or it is located too far away from the Nucleus, you will need a device that can handle the network stream transport of your choice (RAAT, Airplay, Chromecast, etc). Such a device could be an off the shelf Roon Ready streamer or it could be something as simple as a Raspberry Pi running RoPieee or DietPi (or even Raspberry Pi OS if you want) and with Roon Bridge installed on it. A low cost 2GByte Ram Raspberry Pi 4 can be put together for less than £100 in the UK - including power supply, heatsink (you would probably want one - but no fan would be required) and a case.
If you go the Raspberry Pi route and your DAC supports USB Audio, then the Raspberry Pi will be all that you need. If the DAC requires another digitial input (for example, SPDIF over coax or toslink) then you may additionally need to buy an audio HAT for the Raspberry Pi in order to provide the physical interface.
If you want to go the Roon Ready streamer route, then there are a plethora of devices ranging from a Wiim Pro currently on sale in the USA for ~$126 (or around £150 in the UK) to devices going for many thousands of $/£.
The fantastic thing about Roon is that there are always lots of choices!
The curse of Roon is that there are always lots of choices!
Not unless you want to move your headphone setup away from the Nucleus location for some reason. For instance, I have my Nucleus sitting close to my router and connected by ethernet. My listening locations are in other rooms connected to my network by ethernet or WIFI. Therefore, I use an Oppo 203 connected by ethernet, RPi4 connected by ethernet, and RPi4 connected by WIFI for three different endpoint locations.