McCormack DNA 0.5 vs. DNA 2.0 Deluxe

I will support and add to what you heard from @soix .  There are other reasons not to move forward with the DNA-2.

I have considerable experience with McCormack/SMc Audio having first owned a DNA-2 years ago, then the DNA-500, and currently a pair of their upgraded DNA-1 based monoblocks, their upgraded TLC-1 based preamp, and their DAC-2 in my system.

After they did a fantastic job on my TLC-1 preamp (it is basically a VRE-1), I had them upgrade a DNA-2 amplifier.  The DNA-2 is slightly different from other McCormack amps in that it was designed by David Reich (from Theta) and is a dual mono design.  I owned a standard DNA-2 many years ago and at the time I really enjoyed its big, rich, bold sound (it outputs 100A of peak current!). I sold that first one and years later I purchased another DNA-2 and had it upgraded by SMc Audio.  However, in my case, the DNA-2 upgrade did not provide the SQ I was looking for, so Steve and Patrick at SMc Audio helped me find a buyer and then eventually modified a pair of DNA-1s for me, turning them into 650wpc monoblocks, which sound outstanding (e.g., I chose the upgraded DNA mono amps over Clayton M300 Class A monos and Lamm 1.2 Reference monos, all which I owned).  The DAC-2 is quite recent and shares time in my system with Mojo Audio's Mystique EVO Pro DAC.  You can see pics of my SMc Audio gear (and probably an older pic of the DNA-2 upgrade) on my virtual system, except for the DAC-2 which is not yet on the VS but can be seen in my post dated 11-11-23, on this thread.

Back to the DNA-2, it is mostly no longer supported by SMc Audio so you would not have the ability for future upgrades.  It may be repairable, but maybe not.  I am not sure whether it is still supported by McCormack Virginia (i.e., Conrad Johnson) but you might want to check.  

However, if you like the sound of your DNA-0.5, your better option IMO would be to contact Patrick at SMc about upgrading.  If you also need/want more power, talk about having them build a pair of DNA-0.5 monoblocks for you.  All you need is another DNA-0.5, and it doesn't even need to work since they only use the case and heatsinks!  One of those just sold in September for $650.  A pair of upgraded DNA-0.5 monoblocks should be able to drive just about anything and should sound awesome.  A phone call to Patrick would be well worth your time IMO.  You can tell him that Tim suggested you call.  Good luck with whatever path you choose.

definitely call SMc , and lose the Spotify, it makes everything else irrelevant...

Qobuz & Tidal = CD quality = 14,100 kbps

Spotify Premium = 320 kbps (less than 25% of CD quality)

+1 on the recommendation to drop Spotify and switch to Qobuz. 
as far as the amp upgrade…man that’s a tough one…looking at that system…I would probably add an external DAC between the 851 and a Jumbo Shrimp. The DNA-0.5 is a capable amp and if it drives those KEFs without breaking a sweat, like I said, adding a DAC would be a nice step up, provided you ditch Spotify and get Qobuz

I'm so pleased to see a discussion of the great stereo work of Steve McCormack; a most important audio designer,

I bought a DNA-0.5 amp and TLC-1 preamp in the late 90's. I started talking to Pat at SMc Audio about upgrading both a couple years ago. I was 1st going to upgrade the preamp because it lost a channel and had no remote volume control. But then I got into digital streaming and not needing a preamp, instead sold the TLC-1 back to them and upgraded the DNA. Originally I'd bought it for around $1.5K and after putting a couple of grand into the upgrade I have a power amp equal in sonic quality to any in the $6 -8K price range.

Pat is so easy to work with. No desire to up sell anything. Totally committed to providing what the customer needs. He takes all the time you need to decides what you want him to do. I'm so glad I've upgraded this classic piece of stereo equipment. My only regret is that maybe I should have kept the TLC. All I know is my system sounds great and the power amp is a main component I'll never have to replace!!