Is there a difference in sound quality when streaming TIDAL Vs CD player


I hard wired my modem located in my family room using Cad6 cable to my Apple TV and direct wired my Apple TV to my ARCAM AVR550.  I have an OPPO 203 connected by both an RCA cable and by HDMI to my ARCAM.  

The dealer I purchased my ARCAM from told me to play my CD’s through my RCA connection and to watch DVD’s through HDMI.  If I listen to CD’s through the RCA, aren’t I using the DAC on the OPPO player rather than the DAC on my ARCAM and wouldn’t the DAC on my ARCAM be a better DAC.  My friend told me I should use a digital cable rather than an RCA to improve sound quality to utilize the DAC on my ARCAM?  If this is the case, wouldn’t the HDMI be the same as by using a specific digital cable?  I listened to my CD’s through the RCA Vs the RCA cable and I thought it sounded better through my HDMI cable.

i will be looking forward to your responses.

Thank you,
128x128larry5729
I am going to address the Tidal v CD issue. I play my CDs and stream TIDAL on a Cocktail Audio X35. The X35 is a "Swiss army knife" device and one wouldn’t assume that it is as high a quality device as it truly is. Since I stream Tidal and play CDs on the same device the circuitry and ESS Sabre³² Reference DAC are the same and there are no interconnects in-between to effect sound quality and timber; I would pronounce my comparison to be about as true an A-B comparison as one can achieve. The rest of my system is also high quality. The X35 is connected to my Indy Labs Aragon 8008 with Synergistic Research Resolution Reference ICs and the amp feeds a pair of Maggie 3.7i and a Definitive S4000 powered sub. My system nearly doubles the cost threshold of 10K another contributor mentioned. The bottom line is to my ears the sound of Tidal streaming HiFi v playing the same album on CD is nearly indistinguishable. Tidal streaming in MQA is IMHO also difficult to distinguish except on stellar albums.
The different formats are only as good as the hardware you render it on. The very best SACD/CD transport as a digital source is better than anything else. Anything less than that can go either way.
“Tidal HiFi is superb for playing from cars, mobiles, and up to 2000$ fixed gear”

This is the most absurd opinion I ever read anywhere on these forums. The difference in sound quality varies due to the original master used for a CD or Tidal streaming and playback hardware.

Majority of the content available on Tidal HiFi is of CD quality or better. I won’t comment on MQA due to various controversies surrounding the process.

I am now listening to Qobuz and their content in 24/192kHz or 24/96kHz is definitely sounds better than MQA, IMO.

I’ve managed to trim down my CD’s and SACD’s collection to now 250 (from 900) that apparently source from superior master than what’s currently available on Tidal or Qobuz.
Cd on a good player/dac Audio Research Ref9 or fed to PS Audio Direct Stream dac- redbook sounds as good or better in most cases. My 2 cents
I never heard of Qubuz.  Do you need to buy a decoder to use the studio version?

What does DSD stand for?  There are so many acronyms you all use that I do not understand.  Wonder if there is an acronym dictionary?