I own a McCormack DNA-0.5 and a DNA-1 rev A+. The DNA-0.5 is a great sounding amp at its price point, but it does have its limitations. It has good bass response, sweet highs, and is very easy to listen to, but can run out of gas with complex orchestral passages at high volumes. Kris at SMC-Audio said the DNA-0.5 is most likely limited by its smaller transformer. The stock DNA-1 has a larger transformer, but have also heard that the stock DNA-0.5 sounds smoother.
I bought an early 2000 version of the DNA-1 rev A and thought it was voiced to sound like a tube amp. It was very smooth, almost too smooth, but its bass response seemed rolled off and not as dynamic as the stock DNA-0.5. I have to qualify that there was a problem with the regulator circuit, but the amp played fine as the circuit was automatically bypassed; however, I don't think this impacted the sonic signature. I sent the DNA-1 rev A back to SMC-audio, and Kris repaired the regulator circuit and followed his recommendation to bring it up to the latest mod. Since it was an older rev A, it had mods that improved the sound, but ones that are no longer implemented in the standard upgrade - so, I'm calling it a rev A+. Kris thought that the stock transformer was fine and recommended other mods rather than upgrading to the Plitron transformer, and changed the feedback to improve the bass response. The amp now sounds really good and surpasses the stock DNA-0.5 in every way.
If you are going to upgrade an amp, I'd recommend you find either a stock DNA-1 or an already modded DNA-1 that can be brought up to spec. This will be give you more power and you won't necessarily have to upgrade the transformer like you would with a DNA-0.5. Also, pay careful attention to the shipping instructions on the SMC-audio website and double box the amp using as much bubble wrap as will fit.
