Thank you for the comments. Here is what I am finding.
Before replying it may be beneficial to list my system - DarTZeel pre + amp, dCS Rossini APEX, Stenheim 5SE, Siltech 680 speaker cable, Siltech 40th anniversary XLR interconnect. Dedicated home run line into a dedicated listening room. This new system replaced a previous 25 year Naim 552/500 DR system with Cryo’d Hubbell outlet (Hubbell standard operating procedure for Naim USA owners).
In terms of the effects of Rhodium and mismatching plating materials - not so in my scenario. At the time I installed the GTX-D R I also obtained a Furutech DPS 4.1 FI-50 NCF R plug and iec cable. Rhodium with Rhodium. I allowed the GTX-D R to get 350 hours before really passing judgement - it ultimately had 700 hours when I pulled it out. Using the Furutech 4.1 power cable direct from wall to DarTZeel amp was not pleasing. Running the 4.1 from GTX-D into a Torus RM20 and then using a Power cable from the Hubbells of the Torus to the DarTZeel was better tonality wise. Some of what I did not like about the Rhodium “sound” was removed
You wrote:
“I think gold plating adds a warmth and sameness to the music that compromises fidelity, for that reason I think it's the worst choice possible. I'd take unplated copper or even bronze over a gold plated AC power connector anytime.”
So does this mean you do not like the Furutech GTX-D Gold plated outlet? Does it not fall into the “worst choice possible” category for you by virtue of the fact it is gold plated? Just curious as this outlet is now my Hail Mary before I abandon Furutech outlets. While it is not available in a NCF version, I hope I am getting some of the NCF goodness by using the NCF wall plate and outlet cover
Likewise and continuing:
“I'd take unplated copper or even bronze over a gold plated AC power connector anytime.”
Can I take this to mean I would be better off returning to my old Hubbell or even a Shunyata CopperCon (which is a rebranded Hubbell) outlet? What about my Siltech power cables I now have in - 880 Classic Legend Silver which come from the factory by default with Furutech gold plated plug and iec?
Hopefully these two points above do not imply the only worthy outlet to consider is the GTX-D Rhodium or bust? I hope not. The verdict is still out on the GTX-D Gold I am testing as it only has 75 hours on it. I can detect, however, a case may be made for some of what you state gold does, however what is one to do if they are not happy with the “sound” of Rhodium which several do not like? I liked the reduced noise floor and increased resolution from Rhodium. I did not like the change in tonality and increased leanness (reduced warmth) it gave me.
The Torus removed some noise that you attributed to the sound of rhodium. This is what happened when Furutech NCF came out, the previous non-NCF parts were often exactly the same and I compared a lot of NCF parts to their otherwise identical predecessors. NCF does measurably reduce noise, and the NCF parts got rid of a glassy, bright sound that most people attributed to rhodium, but the electrical contacts were exactly the same. So it was noise, not rhodium, that was the source of the glassy, bright sound. The noise was not recognizable with gold plated parts because gold smoothed out the effects of the noise.
Also, I think the reduced noise floor you noticed was a result of NCF material and not rhodium. If you end up preferring gold, Furutech does make one plug, the FI-46G, with NCF material, but I'm not sure they make any other gold plated NCF parts. They do make some NCF parts that have no electrical contacts like the lifters, braces, and outlet covers too. These will all contribute to a reduced noise floor.
Personally, I do not like gold plating because it reduces resolution and adds a noticeable warmth to the sound. Warmth is good to a degree, but it matters how it's achieved and I think with gold plating it has more of a tradeoff vs warmth from other sources, like vacuum tubes. This is especially true with AC power, although the effect is also very noticeable with interconnects and somewhat less noticeable with speaker level connectors.
In general, the result of AC power gear seems more complex and less predictable than other aspects of a system. If you add in active filtering it can get really complex with interactions between reactive components in the filters and the power supplies. Therefore, I think AC power is one area we have to be careful with, it's really hard to pin down the cause of what we hear. It's also why some of the most popular distributors are passive. Active can work well, especially when you have dirty AC power like at an audio show, but it's always a double-edged sword.
There aren't a lot of companies who make a full array of AC power parts designed to all work together. Furutech does, and for me and my preferences, I think Furutech NCF AC power products are as good as it gets. It's not the only way to go, but mixing and matching different brands who use all different materials may or may not produce excellent results. It's very likely there will be a lot of trial and error involved. I think the big issue is NCF parts are not warm, and it's really as simple as that. In cables, it's the hardest thing to account for, as the preference for warmth varies so much from person to person and system to system. When you remove warmth, it's also very common for that to reveal some aspect of the sound you don't like, which could be from anything including the recording itself, but it's most common to blame whatever part was inserted for testing that isn't as warm as the part it replaced.
