Bel Canto Dac 3

yes, if there is a simple mod, consider it.

I had the DAC 2.5 and now have the 3.7 DAC. 

i have not heard the DAC 3, but I have read that it leaned a bit with some digital etch (top end). if that is so, how about running the DAC 3 through a tubed preAmp, then your amp, which could be SS/tube/NCore Class D. the older ICE modules for Class D still have some etch, the NCores typically do not. 

and using some cables that are not lean, but warm and detailed with great dynamics such as Triode Wire Supply. I use their ICs, and Pete's "Digital American" power cables that are made specifically to reduce digital glare. they definitely help. I run one into my DAC, my CDP, and my Class D amp

 Yes that is true of the Dac 3. It’s alittle harsh. I am now, as of yesterday running it through an AVA Fet Valve CFR Preamp. And that has made a huge difference. The upgrades/mods through 3 parties aren’t cheap. Bel Canto doesn’t have any upgrades for this anymore.   

Buy a new or newer one. There are so many for sale here I am sure you will find one to your liking. 

FWIW, I found the DAC 3.0VB to be a big step up in sound quality over the non-VB version -- I got to demo both in my system a while back.  While I'd be happy to have the VB in my system, with all the developments over the past few years I'd probably try something like the Metrum Hex DAC available here now for $1250.  Best of luck. 

But I can’t emphasize enough how much dirty electricity makes digital etch worse. To combat this, I use a power isolator into a conditioner into my Electronics

Are you talking stray DC current? I pretty much have that covered...

Or you talking other power transients? I am running a PC power conditioner into a Adcom ACE 515...

Have the 3.0 and I concur that power is important. The 3.0 sounds better with a good power cable over the stock power cord, so therefore I'd assume that a dedicated power supply helps -- obviously that's why Bel Canto offers one although I do not.
   I don't notice any jitter harshness with 3.0 fed by a Bryston BDP1 streamer, but, what I do notice is just a little opaqueness to the presentation that I did not expect;  using the old Audio Alchemy DTI in the signal path helps slightly.