Dave, first my mistake: I mistook you for Mark of Sablon (I'll correct earlier comments in that regard if I can) Your discussion of changing inlets is exactly what he tried to convince me to do. (I actually bought a couple and then decided doing those kind of mods was not what I wanted to do). Look it, it really doesn't matter to me whether you are correct or not. All it counts is my ears. I heard what I heard with the Sablons (and others) and didn't like it. I'm not speaking for Alex of WyWires, but apparently he is of a similar opinion.
The irony here is that you built me a copper 5V lead to use between the Hynes SR4 LPS and iFi spidf iPurifier, and I love it. In fact, when the first one wasn't long enough, you rebuilt it and I was (and remain) grateful. Thank you.
Ok, no problem. I don't see that both myself and Mark advising our customers to use matching receptacles and inlets as being a bad thing though. I can assure you our intent is not to sell you more stuff, it's to help you achieve your goals in audio reproduction as best we know how.
The AC and IEC plug are both halves of the same connection, with the other half being the receptacle and IEC inlet. I don't think you can look at these parts in isolation, the audio system is a system and every part matters. The ONLY reason people don't consider the receptacle and IEC inlet is because they are more difficult to remove and replace. but they make as much difference as the plug on the power cable.
Component and home manufacturers don't tend to use the most ideal receptacles and IEC inlets. So when considering spending thousands on ideal power cables, why not also spend a little on the other halves of connection? IEC inlets are about $100 and duplex receptacles just under $300. That's about $200 for each power cable to have a receptacle made with IDENTICAL materials and plating rather than whatever random materials that were likely chosen for their low price rather than their sonic attributes. It wouldn't be difficult to hire a local tech to help... well these days that may not be the case but usually it is.
I also have no doubt you experienced what you did and am not saying you didn't hear what you claim. I'm also not saying that rhodium wasn't the cause either. It's just more complex than that, and looking it as rhodium being the cause isn't correct because it's the combination of materials that is causing the issue rather than any one material in particular. If rhodium ALWAYS sounded hard and edgy nobody would buy rhodium. It's not like everyone that uses rhodium experiences hard and edgy sound, so there must be more to it....
Also, I build all my own amplifiers and speakers so I also have a lot of experience with RCA jacks, binding posts, internal speaker wiring, etc... it all matters.
Edit: also good to hear on the DC power cable, for those I do stick to gold plated Oyaide plugs as almost all dc power inlets are gold or nickel plated. It seems like every LPS manufacturer has to go on Alibaba and find a bulk deal on some obscure connector though, it's incredible the number of weird off-brand electrical connectors people ask me to use when making dc cables, many time Amazon or Alibaba are the only places to get them.