You will connect the digital sources using a 75 ohm coax digital cable, not less than 1.25m in length. Good coax cables have BNC connectors on both ends. Your equipment has RCA connectors, so you will use RCA adapters on the BNC connectors so you can connect to your equipment.
Your CD player and Apple TV both output high levels of jitter, so it is important to reduce this as much as possible. Jitter is the #1 sound quality issue with digital audio.
The best way to reduce jitter is using a Synchro-Mesh reclocker in-line in the Coax cable. You can run both the Apple TV and the CD transport to the Synchro-Mesh and then one cable to the DAC1. You can select between them using the switch on the front of the Synchro-Mesh.
http://www.empiricalaudio.com/products/synchro-mesh
Here are plots showing the difference in jitter when using the Synchro-Mesh:
https://www.audiocircle.com/index.php?topic=154408.0
You will need a cheap coax cable to go from CD transport to the SM and a Toslink cable from the Apple TV to the SM. Here are good cables to use for this:
RCA adapters for the BNC cable:
Here is a good cable for the AppleTV to the SM:
https://btpa.com/TOSLINK-XXX.html
The best cable for the money for output from SM to the DAC-1 is the Standard BNC from Empirical Audio for $275. See the jitter plots here:
https://www.audiocircle.com/index.php?topic=154425.0
The difference with low jitter like this is significant. Jitter is like looking through a dirty window and the SM cleans it so you see everything with ultimate clarity. Dynamics, focus, imaging and soundstage are all improved. 30-day money-back, less shipping.
Steve N.
Empirical Audio