Cardas or Nordost for Simaudio/Magico

I owned 330a and heard Magico A3.
I think Nordost would be a better match with A3 than Cardas. 
I would also consider mixing and matching different brands of cables. 
 

To start with, leave the Transparent PC on the 330a for time being as well as the Tsunami. 
Start with speaker cables and interconnects. In this order. 

Also consider trying Audience FrontRow speaker cables. In my system they were betrer than Tyr 2. And I’m running Tyr 2 XLRs. 

 

@dokosan I’m familiar with AZ cables. They lean warm sonically but they’re not bad cables. If you had stock power cords I would say start with power. 
Another reason for my recommendation on the order/approach is that in my experience stating from downstream components will make most difference, good or bad. That order is - speaker cables, interconnects between pre and amp, then move on to the interconnects from source to pre. If you want to start with power cords, the one on the amp will make the biggest impact - amp is what drives your speakers and if you have subpar cables there you have a bottleneck. 

The reputation I’ve heard about Nordost is that they’re bright. IMHO, this isn’t a good match with Magico.
 

The first generation of nordost were a bit thin sounding. 
I would not call the current gen Heimdall 2, Frey 2 and Tyr 2 bright. Fast, accurate and transparent yes. I would also not recommend using Nordost in a system where certain sonic quantities need to be masked. It’s all system dependent. 

Haven’t heard Valhalla in my system but…Frey 2 is better than Heimdall 2 and Tyr 2 is better than Frey 2. So each step up the line gives you a more refined sound, better details and lower noise floor. I can’t imagine Valhalla not beating Tyr 2. 
But as I said earlier, it’s system dependent. For me personally a full loom of any cable manufacturer never worked. At some point you end end with too much of a good thing. It’s important to balance it all in this case using different cables.