Pls Recommend Streamer Under $500 for Tidal “HiFi”

I’m searching for the best sounding streamer under $500 that supports Tidal’s “HiFi” lossless playback. I understand that r2r DAC is desirable, and if possible, I’d like to use the streamer as a DAC for my CD transport and play and store files from my NAS. The unit doesn’t need to have a preamp / integrated amp as I’ll be connecting it to my existing preamp which is feeding vertically bi-amped Energy Reference Connoisseur 70 speakers. Thanks for your suggestions!
I think you are confusing terms or using them differently than typical.  You want a streamer, but then want to use it as a DAC.  A streamer sends a digital stream, typically over a network, to an endpoint that contains a DAC.  Alternately, it could be a local computer with a USB output driving a DAC. 

Typical endpoints are special purpose computers with a network input (Ethernet, WiFi) and either USB output to DAC or often as an appliance, have a built in DAC and put out analog to a preamp/integrated (or even amplified analog to drive speakers).
What functions are you really asking for?  you have a CD player. Do you have a DAC?
I'd personally get a good DAC and run Roon on a computer.  Never play a CD again once you rip them.
The Bluesound works great with Tidal the app is really good.  Over $500 would give you a bunch of other options but under the Node 2i is the clear winner.

Add a R2R DAC later if you like no problem but it's quite good on it's own.
Just a note to Mazian ... the Cambridge will do Tidal but not Tidal Masters which the Bluesound Node 2i does very well! 
Elac Discovery DS-s101 G Was $1000 plus, now you can find close-outs for approximately $500. Very versatile performer , includes Roon subscription.
I have the Bluesound Node2 and it works great with Tidal MQA.  Also works great with Qobuz.
I have a Raspberry Pi ($35) with a HifiBerry Digi+ PRO ($40). The Raspberry runs Volumio with a MyVolumio subscription ($40/year) that streams both Tidal MQA and Qobuz. Volumio can also play files stored locally (USB drive or SD card) or on a NAS (ethernet or WiFi) in all formats and resolutions. It is operated through a web browser on a device of your choice on your local network. The Digi+ is a HAT for the Raspberry Pi that uses I2S to connect directly to the CPU (no USB conversion) and provides SPDIF and Toslink outputs for your pre amp. I use the DAC in my Peachtree 220SE integrated amp. The Raspberry Pi cannot be used as a DAC for your CD transport, but other than that is a cheap and very effective setup that sounds fabulous...
Is the Bluesound Roon ready? Can it be used as a Roon end point? Seems to be no firm answer as I looked.  
You should checkout the PecanPi Streamer from Orchard Audio.  Leo was very helpful with all my questions. I have been very satisfied with my purchase.  I use as a Roon end-point and stream from tidal.
Good choice. I'm using one for one of my Roon endpoints and plan to get a couple more for other zones in my house. 
I have a similiar set up to double-dutch above.  I use a Raspberry Pi3b
(Raspberry has the Pi4 now but the 3 is more than sufficient) with a
Pi2 Design 502 Dac, with a case from their web site. $124. This can be used as a stand alone dac but is better to use for SPDIF out. I run that with Moode software, just download onto a MicroSD card and run.  Easy.  This goes into a Schiit Modi r2r Dac. $250. I run a Bubble Upnp app on Android phone or LUMIN on iPad.  You’ll need a digital cable also.  I lived with this set up for a couple years on my highly resolving system, and I don’t think you can do better for under $500.
Pi2 Design has a newer hat for a little more also. Check their web site.
All this stuff requires a DIY approach, but it isn’t difficult, and probably sounds better than commercial stuff much priced higher.
Put it this way, I upgraded the Dac to the Schiit Yggdrasil and the Raspberry / Pi2 Design setup has not held it back at all.
 I can actually hear differences between different digital connections.
First impressions on unboxing the Node 2i:

”I wonder how much this fancy box and cloth bag that the Node 2i came in cost me?”

“I hope the crappy throw-away interconnect cables that are included didn’t cost me much”

”Why would they fold the CAT5e cable?”

Setup and First listening impressions of the Bluesound Node 2i:

Setup was a breeze. The iPhone app immediately found the Node 2i, which I had plugged into the same network that my wireless access point resides on. After applying updates the unit came to life and I added my Tidal account. Strangely, there wasn’t a menu option to choose Tidal MQA. 

I found menu navigation in the iPhone app fairly inorganic. There didn’t appear to be a way to jump between music playing sessions and individual device tweaks without navigating all the way to the root menu. There should be a simpler way. 

Sound quality seemed good on a non-critical listening session with a pair of Yamaha powered studio monitors connected. I am unclear about the symbology I’m the track list: on the right side of the list, the second last column shows a grey circle with a squiggly line, perhaps the intent was to look like an oscilloscope display of an audio signal. Does that have any bearing over whether the stream is MQA or not?
If you use the analog outputs on the Node2i you will get MQA. 
If you use coax or toslink outputs you will not get MQA, unless you connect to a MQA enabled DAC
Seems that many high end DACs don’t support MQA. Is it too early to expect widespread support of MQA? 
If you use the analog outputs on the Node2i you will get MQA.

If you use coax or toslink outputs you will not get MQA, unless you connect to a MQA enabled DAC
You get the first unfold via these connections, (as long as it's a MQA Master track). True, you don’t full MQA, but the first unfold is pretty good.
You get the first unfold via these connections, (as long as it’s a MQA Master track). True, you don’t full MQA, but the first unfold is pretty good.

I didn’t know I that about the digital connections. Thank you.
I don't remember the brand, but Chris at Audio Advisers in West Palm Beach, recommended a $500 one.  Give him a call. They sell Audio Research, Mac, B&W, Wilson, and LP's that can be from $1500 to $2500., so they are serious listeners, and they never, ever disrespect another company's products.  If you go on their website, that gorgeous TT on the opening page is only $27,995, I believe.
heard the Bluesound 2i last week streaming lossless to some PSB T2's   sounded very good using it's internal DAC.  however i read an article where the Bluesound was put on the test bench and did not measure so well.  go figure.