I had previously owned the Nova300, so my review is based on my experience between the two

First let me state that I really liked my Nova300, that was the reason I stuck with Peachtree, but with advancements in class D amplifier architecture, I was interested in possibly enhancing what was already great.

Comparing the Nova300 to the Carina X….

I wanted to first compare just the amplifiers of two units, so I connected my Topping D90(AKM4499) to the switcher and then to the Aux input of each amp. I played multiple test tones through both units and volume matched them to the same db reading at the listening position. For reference, at the point where the 4th light volume indicator on the Nova lights up, it is equal to -35 volume level on the Carina X
I started off playing Sarah Jarosz “Gone Too Far” from Amazon HD through my Bluesound Node2i. Switching between the two units, there was already a clear difference. The first audible difference was that the Carina X had more “airiness” and detail in the vocal and treble range, while brighter, it didn’t sound harsh, just unencumbered, I continued to sample songs from Chris Rea to Shawn Mullins to Tool. In all instances the imaging and depth between the two was comparable, but the detail on the upper frequencies with the Carina X was the clear winner.

DAC
With there already being a significant difference in sound between the amps of the two units, it didn’t make a lot of sense to directly compare the DACs. With the Nova I was actually using the Topping D90 for DAC duty, as I found the internal DAC of the Nova to sound too tinny and metallic with my particular setup, so I decided to just test internal vs external on the Carina X. In this case, I connected the Bluesound directly to the Carina through TOSlink and then the Bluesound also through the Topping D90 with Coax and then through RCA to the aux input on the Carina. This allowed me to switch back and forth with the inputs on the Carina. Again, there were big differences between the two. I had initially picked the D90 as my DAC because it smoothed out the treble and sounded more pleasant in the setup with the Nova, and in my initial testing with the Carina using just the external DAC, there were obvious differences between the two and it still sounded even the external DAC through the Carina sounded more detailed, however, going between the internal and external now on just the Carina, by comparison, the external DAC almost sounded Muddy and muffled. The Carina was already brighter sounding than the Nova, but this took it to another level. And by brighter, I don’t mean harsh or fatiguing, just clear and detailed and more natural (certainly not clinical) and not the tinny and metallic feel I got from the Nova DAC initially.

DAC Filters – This was something I was particularly interested in as I wasn’t sure if I would be happy with the DAC, but thought having the filters would at least offer some customization and allow me to get closer to the sound I wanted. Playing around with the filters, I can definitely say I can hear a difference between them. I prefer the M-Slow setting as i was able to perceive a smoothing of the highs with some media that was more pleasing to my ears.

Other Observations
1. The pre-out output levels on the Carina X are lower than they are on the Nova300. If you are using these to connect to subwoofer(s)it’s a noticeable difference

2. I prefer the brushed aluminum on the from panel of the Nova to the muted Gray on the Carina
3. I wish the Carina had at least one more TOSlink input and possible one more set of Aux inputs just to have more flexibility
4. I am not sure what observable difference is between the Digital volume control vs the hybrid mode (I currently have it in hybrid)
5. I like the digital display and being able to tell what volume level you have it set at
6. The Carina X while having a smaller vent port on the top has much brighter internal lights the emanate in a dark environment.
7. The green LED power indicator on the front of the Carina is more distracting and annoying than the blue light on the Nova
8. It takes longer for the source input to connect after making the input selection after powering up from standby mode. This can be slightly annoying if you start your music before waiting for the input to acknowledge
9. I wish the tape loop inputs/outputs were available on the Carina as it’s nice to have the option of an external EQ
10. The Bluetooth while nice, isn’t necessary with an external streamer and could possibly be forgone in order to accommodate additional inputs…or better yet, follow NAD’s example and have a module you can add that would incorporate Bluesound directly into the device. (I do realize that NAD and Bluesound are owned by the same company, so they may not allow others access to that module)

For me, it was definitely a worthy upgrade for the amplifier and DAC performance alone. I highly recommend this product.