Optical vs coax vs spdif

Depending on the rest of your system and given the quality of the sound in a restaurant environment, the choice of the connection (and the cable)  may not and probably will not make an audible difference.  
Congratulations on getting the CD collection.

@kalali thanks 🙏 the radio station is giving 10 free cds from their library to anyone that comes in tomorrow, if your in dallas Texas stop by New York Sub I’m university park. The CD player is for the home system. Which is pretty badass. 
@lowrider57 the cables sound fine.  To be honest I was actually impressed with the soundstage but I haven’t listen to a CD on a high fi system in quite a while. Are usually listen to my turntable or my DAC with roon. I’m going to get a proper connection and use the AES output. I’ll let you know if I hear a difference 

I've done A LOT of listening over the years to the various digital connection types.  On super expensive gear to mediocre gear.  Almost without fail, I rate them as follows:

1.  I2S  (pretty rare and very equipment specific)
2.  Firewire   (pretty rare and very equipment specific)
3.  AES/EBU
4.  Coax on BNC
5.  Coax on RCA
6.  AT&T ST Glass Fiber
7.  Toslink
8.  USB

Of course this is just my opinion, on my system, in my room and with my music...

@mofimadness thanks! I’m going to try the aes hookup. I’ll let y’all know

Would the same opinion about the signal quality of USB also apply using a Synology NAS to endpoint?