Hi cjf,
My apologies for the delay in reply. I have been traveling every week for the past month, visiting both dealers and hospitals with our new products, so my time to visit forums has been minimal. I am off the road now for a few weeks, so I'll drop in more frequently. Also, always feel free to write us directly with follow up or questions. We are pretty timely with e-mail.
The Denali products should use either an Alpha HC or a Sigma Analog, unless somebody wants to go all the way to the Sigma HC. That, to me, only makes sense in an extreme circumstance such as massive SS or OTL amps into the 2000T, or a complete reference system on the 6000T or 6000S model, such as DCS Stack + D'agostino amps being one example.
Using a Sigma Digital versus Analog shouldn't matter into Denali 6000T or 6000S because of the massive amount of filtering within the unit itself. Still, power cord gauge, wire quality and type still matter and should be considered. My most common recommendation is the Alpha HC. Massive gauge, top quality wire and not crazy-expensive. There could be a further benefit going to the Sigma Analog, but it should be based on how loaded the 6000 models are. If you are on a single circuit and using 5-6 of the Denali outlets including amps, then the power cord to the wall takes on greater importance. If there are 3 or fewer components, I'd recommend spending less. Its pretty straightforward based on the system you are running. I hesitate to recommend the Venom HC for Denali models. They are very high performance products, so it would be a little like putting budget tires on a Porsche. Still a great car, but it won't do all the tricks its clearly capable of. Start at Alpha HC and work your way up based on the system and component, or current load you are working with.
I hope this is of some help. Again, my apologies for the delayed response.
Regards,
Grant