Hello,
I have a DNA-1 upgrade (it’s now called SMc GT-21 Signature). I went with the power block option (I believe mine was the second or third one they made for a customer).
The amp sounds amazing. It’s quiet, natural sounding, effortless, relaxed (yet detailed). I really can’t say enough good things about it.
I happened to have the opportunity to try out another amp that’s almost double the cost of my SMc. I was impressed to find the SMc is significantly better in every way. Most importantly the SMc amp sounds like actual music rather than a sort of electronic approximation (which is how I’d describe the other amp).
Best of luck with whatever you decide.
JJ