Why Rhodium?

Rhodium is an excellent conductor of electricity, it resists oxidation, has low and stable contact resistance, and high corrosion resistance.

Waste of money. Recently rhodium commodity prices have sky rocketed, so it falls into the hi-end trap of 'more expensive, must be better'. A friend, who is a material scientist with a PhD, tells me its electrical properties suggest it worsens current flow. You figure.

Buconero, you'd better have your friend call George Cardas and tell him, since he is pretty big advocate of Rhodium...

I work at a steel mill and just called our head metallurgist and asked him. He said that Rhodium is a very good conductor.

Maybe the more appropriate question is, when comparing a Porter Port which is unplated Copper against an Oyaide or other recepticle made with Rhodium, among other alloys, does the Rhodium outperform the Copper in terms of neutrality, or does it color the resulting signal like we all know that the Oyaide recepticles do.

Is the coloration a characteristic of Rhodium? Is it a characteristic of Copper? Or does the alloy matter?

I picked up a Furutech FI-28M (R) which is rhodium over pure copper. It's very smooth with great dynamics and soundstaging. I also use Kaplan cables. Several with all copper ends, and one with rhodium over copper for my source.

In my experience, the rhodium is generally tonally neutral while adding smoothness, dynamics, and detail. Other platings such as gold or silver may tilt the tonal balance.

Rhodium is a good conductor of electricity but not as good as copper, gold or silver. As Mofi stated it resists oxidation well. It is more durable then the above metals and gives a very smooth finish which is one of the keys to its use.

My experience with rhodium plated plugs is that there is a glare to them BUT I have not tried all the rhodium plated plugs out there (notably not the FI-28M and not the one Paul uses).

Also it is very important to realize that the wire in between the plugs drastically affects the sound as a whole. A plug that results in a great sound on one cord can sound like poop (technical term) on another.

I have never really got on with Rhodium plugs myself although I understand the properties are useful (durable/resistance of oxidation etc).

I think Cpk has it right and it is the wire connecting between that is as important. I think you should try to stick to the same metal through the chain as much as you can.

While I have furutech plugs, in my set up the Oyaide plugs seem to have the edge. A little more solid through the mid and bass.

I use gold over copper (Furutech F1 25 gold series/Oyaide P079/C079) as it seems to let a little more richness through.

Some may consider Rhodium an, "excellent" conductor of electricity, but- to what are they comparing it? Silver's conductivity is 106, Gold's- 65 and platinum is 15 on the Electrical Conductivity chart(copper is considered the reference at 100). Rhodium(rated at 38) is better than platinum, but not as good as gold. It's attributes are durability and finish. Rhodium or Cardas? Personally: No- thank you. The better the conductivity of the material in question; the more transparent it will be. That means you will hear more of what your source(or whatever is upstream) is delivering(good OR bad).

Yeah, but the red, hot stamped Rhodium...
I'm waiting for the Cobalt.

I agree with Buconero. Rhodium plated connectors are, IMHO, a fad. Until recently Rhodium was cheaper than gold, and it does resist corrosion better than PURE silver plating. But it is not a preferred surface for wearing thrust contact conections. Mil-spec and industrial standards call specify gold as the preferred contact surface for gas tight cold contact electrical connections.

On top of that, you guys are kidding yourselves if you believe that the material used for the connector plating will have an enough effect on a signal to be audible, if even measurable.

ANY time 2 different metals come into contact you form what is called a junction. It is called a thermocouple and produces a (minute amount) electrical current. While I wouldn't expect it to be a factor in power or power supply, it could be a large fraction of low voltage circuits, like phono.
This effect, (thermoelectric effect) should drive those nuts who can hear which way a fuse is installed in a power supply.
Rhodium is used in such couples, for many of the properties listed above.

Don't believe me? Get out a steel coat hanger and a piece of #12 copper wire.
Twist the ends firmly together. Use a vice and pliers if you have to. Connect the free ends to a DVM (what? You don't have a DVM? Shame!) and stick a match under the junction. You should get a couple MV, at least.

On top of that, you guys are kidding yourselves if you believe that the material used for the connector plating will have an enough effect on a signal to be audible, if even measurable.

yes this is why, for example if you compare the Oyaide 037, 046, 079 plugs which have the same exact construction except the plating, being silver/rhodium, gold/palladium, and gold/gold respectively, and you put them on the exact same built cord they sound exactly the same! The different color ends are only for WAF and for the fashion conscious audiophile so as they don't clash with the rest of their system.

IMO, the issue is more complex than just conductivity of the plating as a cause for differences in sound with various platings materials.

The FI-28M(R) appears to be the “little brother” to the FI-50, both being made of rhodium over pure copper. I suspect the sonics are similar. I've found the FI-28M(R) to have excellent dynamics, smoothness, transparency, detail, decay, and soundstaging, while remaining tonally balanced, with no glare.

My rhodium plated Kaplan cable sounds slightly more lively and detailed, as compared to the pure copper version. The cordage is the same.

I know that some rhodium connectors use a silver underplating. Perhaps that is the source of the glare?

I don't believe that rhodium will necessarily cause any loss of detail or transparency, as compared to a higher conductivity material. My experience is just the opposite.

I’ve also tried the FI-25Gs, but they sounded somewhat bright, with some glare.

Another example of interesting material is palladium. I use a Pure Note Alluvion digital cable, and the palladium in it sure takes the glary edge off of the silver. However, this is an alloy, and not a plating.

Nickel is another story. It always seems to cause glare for me.

"Perhaps the most interesting fact revealed by this chart is how low most copper alloy materials rank in relative conductivity. One might easily assume that alloys such as the brasses and bronzes, because they are mainly copper, are nearly as conductive as copper. This is not the case. The small percentages of tin, aluminum, nickel, zinc and phosphorus that make up these alloys degrade the electrical performance of the resulting alloy to a far greater percentage than their compositional percentage in the alloy.

One should not conclude from this, however, that brass should never be used in electrical applications. There are instances where the superior tensile and machining characteristics of brass make it a better choice than copper as long as the sectional areas are increased proportionately to achieve the conductivity that a copper part would have in the application. Size for size, however, copper is exceeded only by silver among the materials commonly used for electrical applications."

www.kp44.org/ftp/ElectricalConductivityOfMaterials.php

Couldn't copy the chart but it's at the above website.

Size matters :-)

Rhodium has the best resistance to corrosion over any current material being used for termination. I own several audio components that have been in a cottage next to Lake Erie (high humidity) for 20 years. The heat is off 6 months out of the year with almost constant 80% - 100% humidity. Rhodium is the only material that has not shown signs of surface corrosion under this condition. Silver, copper and gold all eventually broke down with surface build up. Steel connections were rendered useless and couldn't even be cleaned.

A friend of mine and I compared two RCA cables in a blindfold listening test against each other. They were connected between a CD player with a direct output to the inputs of two mono block amplifiers. The cables were two meters long with both using identical wire with no insulation. One set of cables was terminated with a gold plated RCA plugs with soldered connections. The other was terminated with a RCA plug that was rhodium plated, set screwed and soldered. Both of us picked the same interconnect as our favorite over two separate listening sessions. We gave the rhodium plug a slight edge in the area of sound stage size and 3 dimensionality. This is, obviously, not a perfect test of plating comparison. It may say as much about the rhodium set being set screwed.

Willoamp, industrial gold alloys do not oxidize and are considered extremely corrosion resistant. That's why gold is used for virtually all mil-spec and industrial purposes. There are a couple of limitations: 1) gold is not terribly wear resistant, so may not be the best choice for multiple mating cycles. 2) for cost purposes, some cable manufacturers use a thin gold wash rather than a properly prepared and applied gold plating. 3) gold plating can can be problematic if exposed to extreme thermal cycles if the plating surface has not been prepared properly.

Electrically, the best way to make cables is via a crimp connection using a die designed specifically for the cable and connector in question. What you want is what's called a gas-tight connection, and you can't get that via a screw collar. Solder joints are OK, but you need to clean the flux off of the conection carefully because it is hygroscopic and attracts water. Also, solder joins are somewhat fragile and can crck or break under the strain of multiple connections (mating cycles).

I still seriously doubt that anyone can hear the difference between any type of connector plating, unless you are running extremely high current through the lines. And even then...

I still seriously doubt that anyone can hear the difference between any type of connector plating

Does this indicate that you have not tried plugs with different platings? If you have which ones? If not then you have no first hand experience, it's all just speculation. Not really helpful to the OP.

Willoamp- Read this: (http://www.corrosion-doctors.org/MatSelect/corrgold.htm) Especially the first line, which states that gold is the most NON-REACTIVE of ALL metals.

Cpk, I have heard systems configured with all types of cables and connectors. IMHO with regard to interconnects, good connections (NOT connectors) matter most. The actual wire (assuming that you are within guidelines for inductance, capacitance and resistance) almost always do not matter.

Well I hear differences, but my hearing and system are quite good. Granted, some differences may be subtle, however others are quite obvious. For example, silver sounds very different than copper.

Just this weekend I've been comparing outlets, the Hubbell 8200/8300 and 5362. The only real difference is that the 8200/8300 has nickel plating whereas the 5362 does not. The presentation is different, with the 8200/8300 being more forward, brighter, and a bit of glare. I attribute the differences to the nickel plating.

I have a friend that is a cable denier. Whenever he comes to my house he pokes fun at the fat hose pipes that adorn my system. Last time he was over he commented that I had more bass then before, and what had I changed. When I told him it was only one IC and a PC, he just grinned.

Br, listening to a system configured with various types of cables/connectors and making up cables and changing only one variable like the plug, or solder used, or connector used are two different things. Most people are shooting for a balanced presentation and there are many ways to get there so hearing different systems with different cables and having people getting somewhat similar result’s is not terribly surprising. But I know I could easily throw it off inserting one or two well chosen pc’s that would exacerbate a systems flaw.

With a few companies the only difference between the certain plug models is the plating, all else being equal so then you are only hearing or not hearing the differences afforded by the plating.

Just for shits and giggles I would try building a pc and changing only the plugs preferably only the plating, try it on your cdp and I am sure you will hear a difference.

I do agree though crimping is the way to go.

Interesting discussion so far.

Here's an experiment I tried several weeks ago, although it's not specifically about Rhodium it is related to the conversation.

I've been using an Acrolink 6N-P4039 PC terminated with Oyaide P-004 & C-004 on my amp. I like this cable a lot in this position. This is a high purity copper unshielded cable. The Oyaides are beryllium copper plated with platinum then palladium.

I replaced the Oyaide C-004 IEC with a Fim model 302 IEC. The Fim is gold plated high purity copper. This one termination is the only change I made to my entire system.

The deep bass and punch diminished significantly. I was surprised how much difference I was hearing because, frankly, I expected any difference, if audible, to be subtle.
When I replaced the Oyaide the bass returned.
Note: Male Oyaide was plugged into Oyaide R-1 outlet.

I did this experiment because the amp IEC is a gold plated Furutech and I thought like metals might be the way to go.

Footnotes:
1. I like the Fim terminations in other applications but not this one.
2. I also like Fim outlets.
3. I'm not even pretending I understand any of this but it's fun and interesting.

>>10-11-09: Mooglie
For example, silver sounds very different than copper.

Not at all. It depends on the design.

A csble's "sound" depends far more on its' geometry, dielectric, and conductor purity than the conductor itself.

I can conduct a listening session with 10 interconnects and you would never know which is silver or copper or hybrid.

Mooglie,
I agree that nickel probably has no place in audiophile cabling. On an interesting note I found that the elements name is derived from the German word nickel, which means "Old Nick", a name for the devil. I think in this application he's messing with "good" sound. 8^)
On a related note, I'm not sure brass is all that "good" either and I'm trying to "exorcise" it from my PCs as much as possible. It's amazing how much brass is in most PCs even the megabuck varieties.

In my example I was referring to silver and copper platings such as AC and RCA connectors. In regards to cables I would tend to agree to a point. Certainly geometry, dielectric, etc., have a significant effect on the sonics. However, I also believe that materials impose some audible character on a cable. I’m certain there are some designs that may minimize the effects.

As I previously mentioned, the Pure Note Alluvion digital cable I use is a palladium-silver alloy. I’m quite certain that palladium is used to remove the edge off of the silver, and it’s quite effective in my view. Other vendors such as Silversmith and Siltech use materials such as palladium and gold in their cables. I’m not sure one could replicate the sonics of some of these cables via geometry and dielectrics alone.

Rja, I agree, brass is ok, but has limitations. Pure copper tends to sound better to me, and is usually a safe bet for just about any interconnect or PC. FYI, I use a mix of cables and PCs. Some are high purity copper, and some are copper-silver hybrid (separate types of wire). A couple of rhodium plated connector PCs are also used in strategic places.

I experimented a few years ago with two power cables with Acrolink 7N copper wire and one with Oyaide gold connectors and the other with Oyaide rhodium connectors (this was going from the wall to a PS Audio Power Plant Premier). The difference in the sound from just the plating was stark. This is why Oyaide has different types, to voice your system, not WAF as suggested above (though your system may have bottlenecks that keep you from hearing the difference well). In that instance I found the rhodium to be slightly more defined, but it also had some glare. My system had plenty of resolution, so I went with gold to smooth it out and add some body.

I would say the choice is totally system dependent, but I would go with gold to inject a bit of warmth. I don't think relative conductivity is the real issue when it comes to sound. I'm currently struggling with which Furutech plugs and connectors to use in my new setup, because the decision is not entirely straight forward.

I will add that Alex at Wywires has told me he believes that the wire used in the cable does make a big difference on whether you hear differences in plating. He says he doesn't hear much difference between the silver plated connector he normally uses and the FI-50 rhodium.

@fork I’m pretty sure the WAF comment about connectors was pure sarcasm..

I have definitely heard differences between conductors and between different playing on otherwise identical connectors on PCs.

Or I’m delusional. But what a sweet delusion..

Rhodium is a poor to average conductor, only about 35%IACS which is only a little bit better than Brass. It is very tough, hard wearing, and has a very smooth and shinny finish, almost like a chrome finish.

Like all cable designs it would appear that it depends on the cable and connector architecture, that has been utilised.

For me Rhodium tends to have a dryish, perhaps glarish, and darkish presentation which appears to give an impression of detail.

Just plain simple logic states that one is ignoring the physics of science, when Cardas, and Furutech is claiming Rhodium and other 'rare' metals improve 'connectivity' soundstage etc etc. Nothing is further from the truth. These two companies are just fooling you and ripping the fool who believes in this crap. Just simply silver and copper are the only metals THAT SHOULD BE USED FOR A FAITHFUL NEUTRAL transmission of audio signals. Silver is very tricky but after 10 years of studying and testing cables I realized a cable that is perfect. Silver/Copper!  It is absolutely true when someone said that the connections SHOULD BE VERY SECURE. It is also true that after soldering you need to remove the flux. Remember Silver and Copper. Silver is tricky. But copper is THE BEST METAL FOR AUDIO! Period.

Idealy,  if your cable is copper, use a copper connector, and if silver use a silver connector. Marrying different metals is NOT A GOOD IDEA. Learnt these the hard way. A company called Viborg produces pure copper connectors per pair for 50 USD, in Amazon, as good as FURUTECH albeit it costs way way the Furutech. They too sell Rhodium. Touch it not! Just stick to copper and silver, and do not be fooled by any other metal, NOT EVEN GOLD, because they deteorirate very fast, and it causes more problems for the audio signal.

 Rhodium is a bit different than the other metals. Of course...I know we'll that you gents know that. However what I mean, is that rhodium isn't a very good conductors of electricity. It's actually horrible. Better still...it actually repels it. And if said material repels electrons then we've got generation of electricity. As with a magnet. So what I saying is....rhodium is a catalyst. And it's a magical rule breaking reality altering metal. Do you see?

 

It's shiny, but most of the time I find it too hard and slick to offer good grips.

I like my contact metals soft and springy. Hard spades for instance are nearly impossible to tighten well long term. Gold over copper however has enough malleability that the speaker terminals bite into them when tightened.

In power connectors they seem to make it a lot easier for plugs to slide in or out.

I love how they look.  Like jewelry, but never had a good experience with them on a practical sense.

I use Oyaide C-004 on IEC and Viborg Silver/Rhodium on Schuko in my system. My observations is that the plugs not only have an effect on the frequency repons (less warm, more neutral) but also on the time domain. The hard metals don't have the "soft" 'decay' of gold and silver and present a tighter sound with more 'attack', punch and control. They suit my taste of music (rock/pop), but I understand that not everyone likes them.

 

 

1. Poor conductor
2. Hard which makes for reduced mating contact surface.
3. Only used in audio
4. Uneducated consumer

 

I am sure there are more reasons.

Current estimates are a leading edge semiconductor plant costs $10-20 Billion (that's 9 zeros). Even a large geometry analog fab is high 100's of millions. I.e. price is really no object. You will not find one rhodium plated connector in that plant.

 

 

It’s interesting that folks who actually have a credible story / testing to tell about their experience with rhodium connectors vs gold, etc all agree that rhodium is a superior connector metal / material with least impact to the energy and openness of the music signal. 
 

those who don’t have any experience to speak off think it’s a bad connector material. And will never try it. 

Rhodium is not only a poor conductor but IMHO too hard.

To get a good grip on an outlet or speaker or any other contact you want a soft metal.  Something that will deform under pressure, allowing for serious grip, especially for AC plugs, sockets and spade connections on speakers.  Pure copper or gold plated copper will absolutely outperform Rhodium for reliability alone here.

Rhodium, as pretty as it is, is really a terrible choice in this manner. 

Since rhodium is indeed a fairly poor conductor, my assumption is that it is used to plate silver so as to prevent the dulled appearance of silver oxide...EXACTLY like cheap gold plating is used on myriad copper products to control oxidation. The latter's "bling" has rationale in that copper oxide is NASTY...not conductive at all. But silver oxide IS conductive, so plating it with an inferior conductor like rhodium for "bling" is a decidedly bad idea.

OTOH i cannot comment on rhodium's "sound", as the plating is so thin, and its purpose silly, that I completely avoid it. Benign silver oxide needs to be wiped off only perhaps when you pull out grandma's cutlery for company!