Is there an audio difference between copper & silver HDMI cables? - AVS Forum
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post #1 of 48 Old 07-29-2010, 09:42 AM - Thread Starter
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I use a multi-channel system for audio from my player to the receiver and I run an HDMI cable from my player direct to the TV for video.

I have been considering changeing and using an HDMI for both video and audio.

MY question is: Is there and sound quality differences between an HDMI cable that uses copper wire for audio vs cables that use 90% copper with 10% silver OR those cables that actually use 100% silver wires that run the length of the cable?

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post #2 of 48 Old 07-29-2010, 09:46 AM
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You can find hundreds of subjective posts saying "Hell yeah, HUGE difference".

You will not find one post with objective data backing up the subjective posts.

This is digital audio, It either works or it does not work and the cable does not alter the frequency response since again its digital stuff (1s and 0s). Do not get fooled into Jitter debates either again they have no objective data to back up their opinions.

Buy your HDMI cables from monoprice.com or BJC.com the only thing that matters is the actual construction of the cable.

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post #3 of 48 Old 07-29-2010, 12:12 PM
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Silver is a better conductor than copper. For HDMI, a silver plated copper wire will have less loss than a solid copper wire. A solid silver wire will show little if any improvement over a plated wire because of skin effect. Net effect is you can transmit a signal a little farther. Whether that signal is usable is another question. There are many things more important than conductivity in determining how well a HDMI cable will work, things like return loss, skew, and cross talk. Arguably the best HDMI cable available, the BJC Series 1, is solid copper but addresses these things better than other cables.

And as alluded to above, no HDMI cable change is going to improve the sound unless you are getting clicks or drop-outs, or the picture unless you are getting sparkles or worse.
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post #4 of 48 Old 07-29-2010, 12:35 PM - Thread Starter
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Quote:
Originally Posted by Colm View Post

Silver is a better conductor than copper. For HDMI, a silver plated copper wire will have less loss than a solid copper wire. A solid silver wire will show little if any improvement over a plated wire because of skin effect. Net effect is you can transmit a signal a little farther. Whether that signal is usable is another question. There are many things more important than conductivity in determining how well a HDMI cable will work, things like return loss, skew, and cross talk. Arguably the best HDMI cable available, the BJC Series 1, is solid copper but addresses these things better than other cables.

And as alluded to above, no HDMI cable change is going to improve the sound unless you are getting clicks or drop-outs, or the picture unless you are getting sparkles or worse.

Thanks for the info. I called Blu Jean and had a long talk with Jess and he helped me under the differences and the + and - of using silver as a plate over copper or 100% silver vs copper. Basically he said not worth the $$$ because silver, after bending the cable a few times it can start to crack and break down leaving the signal worse off. Plus the differences in audio between silver vs no silver is so slight that no one would hear the difference.

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post #5 of 48 Old 07-29-2010, 01:51 PM
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Quote:
Originally Posted by JimShaw View Post

...not worth the $$$ because silver, after bending the cable will start to crack and break down leaving the signal worse off.

Well, that is total BS, which is incidentally the first BS I have heard from BJC. Talk to Kurt the next time.

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Plus the differences in audio between silver vs no silver is so slight that no one would hear the difference.

More BS. There is absolutely no difference in the audio. The audio is transmitted digitally in an HDMI cable. There is no way the material the wire is made of will affect the sound.

But I agree that there is no need for silver in an HDMI cable in almost any case.
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post #6 of 48 Old 07-29-2010, 02:19 PM
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A long time ago, I spoke to an actual manufacturer of coaxial cable (I know this isn't HDMI) regarding the functional reasons as to why they offered copper and silver plated copper variants. I was told the silver plating offered a couple of advantages but they were application specific. One advantage was that silver protected the copper from surface oxidation. In situations where the frequencies really got up there, like let's say microwave, maintaining the integrity of the copper surface is essential because of the skin effect (skin effect is a phenomenon whereby greater amounts of the signal travel on the surface or skin as the frequency increases). This results in greater longevity for the cable. Another potential advantage is that long term soldering integrity is improved with a silver surface. However, by no stretch of the imagination are the frequencies that we're concerned with in audio approach microwaves. In the end, if you've got a particular concern about the HDMI cable you're using, look to certified cables.

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post #7 of 48 Old 07-29-2010, 03:59 PM
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There is another reason that silver plate is used in RF applications. Oxidized silver is a good RF conductor. Oxidized copper is not.
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post #8 of 48 Old 07-29-2010, 08:48 PM
 
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Quote:
Originally Posted by Colm View Post

There is another reason that silver plate is used in RF applications. Oxidized silver is a good RF conductor. Oxidized copper is not.

That's why exposed area of HDMI cable such as contact points are plated with gold or nickle.
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post #9 of 48 Old 07-30-2010, 10:57 AM
 
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Quote:
Originally Posted by penngray View Post

YYou will not find one post with objective data backing up the subjective posts

Silver can dramatically increase the efficacy of soldering and conductivity, especially important as distances increase. The automatic indictment of silver plating for any cable is another example of cost-hostility, while ignoring potential benefits.

EDIT: Sorry, Chu beat me to it.

http://www.avsforum.com/avs-vb/showthread.php?t=906463

Interesting, although not surprising, that even tin is accepted by some as potentially better than silver. Why? It's cheaper, thus fitting the anti-cable brainwashing.

Even KurtBJC (from a respected company that many here dote over) says silver is better, at least as a plating. Any advantage that can be gained with a cable 25' or over is wise. This includes larger gauge, silver plating, and perhaps a locking connector as additional strain relief. This is due to the simple reality that longer runs tend to be installed in places that are rather costly to remove and re-install, at least in terms of labor and possibly re-purchasing cost.
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post #10 of 48 Old 07-30-2010, 07:49 PM
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I don't recall reading anything about co-ax plating in DX radio and TV discussions. They have much higher frequencies and orders of magnitude less signal to deal with.

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post #11 of 48 Old 07-30-2010, 08:04 PM
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Silver plated copper center conductors are sometimes used in coaxial cables, primarily for enhanced solderability or corrosion resistance. But this discussion is about HDMI cables.
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post #12 of 48 Old 07-30-2010, 08:31 PM
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What are the differences between HDMI cable and co-ax that silver plating would be a factor in one but not the other?

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post #13 of 48 Old 07-30-2010, 09:06 PM
 
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Quote:
Originally Posted by Colm View Post

Silver plated copper center conductors are sometimes used in coaxial cables, primarily for enhanced solderability or corrosion resistance.

Silver tarnishes easily. Gold or nickle plating for such purpose is much more common for a good reason.
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post #14 of 48 Old 07-30-2010, 11:09 PM
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Quote:
Originally Posted by geekhd View Post

Silver tarnishes easily.

Yes, but you would know that the oxide is a good conductor if you read the previous posts.
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Gold or nickle plating for such purpose is much more common for a good reason.

Yes, they are both frequently used on contacts. But neither are commonly used on wire, which is what we are talking about. Gold is is a worse conductor than silver or copper and is more expensive. And nickel is a much worse conductor. Not a factor in the minute quantities used on contacts, but a problem for wires. And FWIW there are RF connectors with solid silver pins.
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post #15 of 48 Old 07-30-2010, 11:27 PM
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Quote:
Originally Posted by Speedskater View Post

What are the differences between HDMI cable and co-ax that silver plating would be a factor in one but not the other?

Now you are starting to getting beyond my knowledge. Both are dealing with RF frequencies. Both have to deal with skin effect. A copper plated steel center conductor is frequently used for cable TV even though steel is a relatively poor conductor compared to copper because skin effect will cause most of the current to be carried in the copper. Silver plated copper will yield even less loss all other things being equal. A lot of critical aerospace equipment uses silver plated connectors for RF because of skin effect and the fact that the silver oxide is conductive. Doesn't look pretty but still works. I have some sitting on my bench right now. And there are coaxial cables with silver plated braid.

Why don't you see silver more often in coax? Because it isn't necessary most of the time. Same thing goes for HDMI. You get something like 5% better conductivity than copper. If you don't need that extra few percent and don't need silver for one of the other reasons mentioned, you don't use it. Besides, you can do the same thing by increasing the gauge of the wire.

Now, if we are consider cable for an aircraft or spacecraft, weight and reliability become important and cost less so. Silver plated RF cables, and even silver plated cables for DC circuits become advantageous.

Don't forget my point, despite the technical advantages of silver over copper, you almost never need it for consumer electronics, particularly HDMI cables where there are much more important factors than conductivity.
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post #16 of 48 Old 07-30-2010, 11:42 PM
 
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Quote:
Originally Posted by geekhd View Post

Silver tarnishes easily. Gold or nickle plating for such purpose is much more common for a good reason.

The major reason silver is not used is because people think the tarnishing is bad because they don't know any better. Silver oxides are silver, and pretty much just as conductive as the underlying silver except that the color changes so it looks crummy, but sometimes it can get sulfurs in there too which would degrade though. Gold doesn't do that so it always looks brand new so people prefer it, again because they don't know any better. Silver is a perfectly acceptable choice for connectors, it's just uncommon in the consumer world is all. But it isn't for any particularly good reason as you seem to be implying. In fact, it is used in applications where people actually know what they're talking about and don't care about the "ugly appearance" of tarnished silver contacts. But it is actually a superior conductor for a contact in many instances. But the difference is negligible in the move to gold which always looks shiny and new and thus leads to satisfied ignorant consumers who think it's 'more-gooder.'

Gold can have advantages because it is softer, and so is better where plugging/unplugging is very frequent if the gold plating is rather thick. Otherwise its softness can actually wear down with very thin plating and be detrimental.

Silver is used in many professional environments and studios, as is gold.
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post #17 of 48 Old 07-30-2010, 11:58 PM
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Funny thing is that gold on most consumer electronics is not nearly the panacea that most think. It is only a few microns thick and quickly wears away. Underneath, if you are lucky is a layer of nickel to keep the copper underneath it from migrating into the gold. And even if the gold does not wear through, apparently even the nickle migrates into the gold. In other words, the gold plating on most consumer electronics is strictly cosmetic.
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post #18 of 48 Old 07-31-2010, 12:14 AM
 
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Quote:
Originally Posted by Colm View Post

Yes, but you would know that the oxide is a good conductor if you read the previous posts.

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Originally Posted by ChrisWiggles View Post

The major reason silver is not used is because people think the tarnishing is bad because they don't know any better. Silver oxides are silver, and pretty much just as conductive as the underlying silver

Silver tarnish is sulfide , not oxide. Silver sulfide is not as conductive as silver itself. Not that it will make much of a difference for HDMI cable's performance but looks could matter to consumers.
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post #19 of 48 Old 07-31-2010, 12:42 AM
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Quote:
Originally Posted by geekhd View Post

Silver tarnish is sulfide , not oxide. Silver sulfide is not as conductive as silver itself. Not that it will make much of a difference for HDMI cable's performance but looks could matter to consumers.

Depends on the environment, often a combination of both and other compounds...in any case, the conductivity is superior to corroded copper at RF frequencies, which is the point. And IIRC, silver sulfide is an even better conductor than silver oxide. No body is suggesting that the conductivity is as good metallic silver. You are aware that silver oxide is used as one of the electrodes in some batteries aren't you?

Who is going to peel back the insulation on the wire to look? Nobody is suggesting silver for consumer cables. Did you even bother to read the previous posts?
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post #20 of 48 Old 07-31-2010, 09:05 AM
 
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Originally Posted by Colm View Post

Who is going to peel back the insulation on the wire to look?

I was referring to the looks of the contact area of cables.
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post #21 of 48 Old 07-31-2010, 10:03 AM
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Nobody suggested silver there for consumer products either.
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post #22 of 48 Old 07-31-2010, 10:14 AM
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Quote:
Originally Posted by Chu Gai View Post

In situations where the frequencies really got up there, like let's say microwave, maintaining the integrity of the copper surface is essential because of the skin effect (skin effect is a phenomenon whereby greater amounts of the signal travel on the surface or skin as the frequency increases). This results in greater longevity for the cable. Another potential advantage is that long term soldering integrity is improved with a silver surface. However, by no stretch of the imagination are the frequencies that we're concerned with in audio approach microwaves.

Actually the on cable clock rate for HDMI can be up to 1.65Ghz so you are into the microwave spectrum by most peoples definition. I believe this number has been raised to 3.40Ghz for HDMI 1.3/1.4.

This is why HDMI cables aren't the easiest things in the world to make.

The transceiver may run slower if your only sending audio, but if your sending a 1080P video signal along with your audio its likely you'll be running fast. There is only 1 clock for the entire link so its not like the audio transmission just runs slower, although they may space out frames.
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post #23 of 48 Old 07-31-2010, 12:03 PM
 
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Originally Posted by xianthax View Post

Actually the on cable clock rate for HDMI can be up to 1.65Ghz so you are into the microwave spectrum by most peoples definition. I believe this number has been raised to 3.40Ghz for HDMI 1.3/1.4.

This is why HDMI cables aren't the easiest things in the world to make.

The transceiver may run slower if your only sending audio, but if your sending a 1080P video signal along with your audio its likely you'll be running fast. There is only 1 clock for the entire link so its not like the audio transmission just runs slower, although they may space out frames.

It is not possible only to send audio on HDMI. Audio rides in the video signal blanking time.
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post #24 of 48 Old 07-31-2010, 01:37 PM
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Originally Posted by ChrisWiggles View Post

It is not possible only to send audio on HDMI. Audio rides in the video signal blanking time.

Sure it is, audio data is contained in the data islands, which also hold any auxiliary data that needs to be sent. Its completely up to the source where to put these islands and your right that they usually are placed in the blanking time for the video feed.

However the spec allows as many data islands as you wish to be transmitted between video data periods. Theres nothing stopping a device from sending a constant stream of data islands, and hence audio, without sending any video data.
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post #25 of 48 Old 07-31-2010, 02:24 PM
 
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Originally Posted by xianthax View Post

Sure it is, audio data is contained in the data islands, which also hold any auxiliary data that needs to be sent. Its completely up to the source where to put these islands and your right that they usually are placed in the blanking time for the video feed.

However the spec allows as many data islands as you wish to be transmitted between video data periods. Theres nothing stopping a device from sending a constant stream of data islands, and hence audio, without sending any video data.

I don't believe the spec says that at all. I am not aware of any device anywhere capable of sending audio only via HDMI, and I am fairly certain this is not possible in HDMI specs.

Even processors which have dual outputs for video to a display and another for separate audio output to an audio processor must also include video, they just send black frames of video is all. Because it is actually the video which determines the data rate available for audio.

I believe you are incorrect about this. It is not up to the source, because what is supported is defined by HDMI spec, and there are no provisions I am aware of for sending audio-only; hence no devices that are capable of sending (or receiving) only audio that I am aware of, because it's not part of HDMI spec.
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post #26 of 48 Old 07-31-2010, 02:52 PM
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Quote:
Originally Posted by ChrisWiggles View Post

I don't believe the spec says that at all. I am not aware of any device anywhere capable of sending audio only via HDMI, and I am fairly certain this is not possible in HDMI specs.

Even processors which have dual outputs for video to a display and another for separate audio output to an audio processor must also include video, they just send black frames of video is all. Because it is actually the video which determines the data rate available for audio.

I believe you are incorrect about this. It is not up to the source, because what is supported is defined by HDMI spec, and there are no provisions I am aware of for sending audio-only; hence no devices that are capable of sending (or receiving) only audio that I am aware of, because it's not part of HDMI spec.

HDMI 1.3 spec is available here

Page 77 of the PDF.

Quote:


5.2.3.2 Island Placement and Duration

The Source is required to determine the temporal placement and duration of the Data Island with
respect to the video signal’s horizontal and vertical blanking periods and synchronization signals. It shall do so following the rules stated below.


All TMDS Control Periods shall be at least tS,min (12) characters (pixels) long.

The Data Island shall contain at least one packet, limiting its minimum size to 36 pixels.

Islands shall contain an integer number of packets. In order to assure the reliability of the data
within the Data Island, they shall be limited to 18 packets or fewer.

Zero, one or more Data Islands can occur between subsequent video data periods.

While transmitting video, at least one Data Island shall be transmitted during every two video
fields.

HDMI is more expensive than than AES/EBU or S/PDIF over XLR/Toslink/Coax at the moment for pure audio applications so i doubt many transceivers have been built for audio only, but thats not a limit of the HDMI spec but rather how designers have chosen to implement it.

I don't know of any audio only products but again thats not because HDMI wouldn't allow it, rather that no one has chosen to implement it as it doesn't have any advantage over current options.

Its added speed only matters for lots of high bit rate channels, which means your watching a movie and need video also anyway. If anyone came up with an audio only application that required more bandwidth than AES/EBU or S/PDIF could deliver you may see some audio only HDMI devices.
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Quote:
Originally Posted by xianthax View Post

HDMI 1.3 spec is available here

Page 77 of the PDF.

Right, but there must be video for those data islands. It is actually a serious desire of many to have a lower-bandwidth audio-only high-res out, but I am not aware of any devices that support this, even in a non-spec implementation of the HDMI physical interface (as there is with for instance Denon-link which is a proprietary implementation of the physical ethernet interface for audio only).

If you look at section 5, you don't see any mention of support for signaling that doesn't incorporate Video, Data, and Control periods. It does make mention of "while transmitting video, at least one Data Island shall be transmitted during every two video fields" but there isn't clear support that I see directly of audio-only (or Data & Control only) operation.

And again, there definitely have been many requests for people hunting for devices that can do an audio-only output, and AFAIK this is simply not possible with HDMI, hence why no devices that support such an option. As I mentioned before, there are processors that have what purports to be an "audio-only" HDMI output, but they simply replace the active picture with all black frames but still must transmit video.

And the video rate also does determine the bandwidth available to audio, and if I recall correctly lower video rates such as for 480p etc cannot support the full range of high-res audio like HD resolutions at higher clock rates do.

This is described more in section 7.3.3:
Quote:


Available audio bandwidth depends upon the TMDS clock frequency, the video format timing, and whether or not content protection re-synchronization is needed.

Further, a representative of the HDMI organization answered this question directly in this thread:
http://www.avsforum.com/avs-vb/showthread.php?t=795465

Quote:
Originally Posted by HDMI_Org View Post

It is true that the HDMI signal does require a video signal (namely, it requires the video clock signal) in order to send audio (which sits in the blanking period of the video signal). However, even a blank/dummy pattern (such as all black) video signal would do the trick, so the audio does not have to be linked with a specific HD video signals.
...



Quote:


HDMI is more expensive than than AES/EBU or S/PDIF over XLR/Toslink/Coax at the moment for pure audio applications so i doubt many transceivers have been built for audio only, but thats not a limit of the HDMI spec but rather how designers have chosen to implement it.

I believe you are mistaken about this, as reiterated by HDMI itself.

Quote:


I don't know of any audio only products but again thats not because HDMI wouldn't allow it, rather that no one has chosen to implement it as it doesn't have any advantage over current options.

Its added speed only matters for lots of high bit rate channels, which means your watching a movie and need video also anyway. If anyone came up with an audio only application that required more bandwidth than AES/EBU or S/PDIF could deliver you may see some audio only HDMI devices.

It would have huge advantage for distributing high-res audio to a device much farther away which is a major obstacle for the huge bitrates of HDMI because of video. If you could extract the audio alone, and send that over an audio-only interface or an audio-only implementation of HDMI then you could go much farther with the signal with much greater ease. Many people have asked for this, and it is not possible, otherwise it would have been done already.
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post #28 of 48 Old 07-31-2010, 08:07 PM
 
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Quote:
Originally Posted by Colm View Post

Nobody suggested silver there for consumer products either.

Whether someone suggested or not, consumer cable termination products with silver plating are on the market.

Nobody is worried about the corrosion in the sealed environment of the inside of coax cable. vvv
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Originally Posted by Colm View Post

Silver plated copper center conductors are sometimes used in coaxial cables, primarily for enhanced solderability or corrosion resistance.

When you bring up corrosion resistance issues, it goes into the realm of exposure. Why bring it up if you don't want to delve into it (quote at the top)?
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post #29 of 48 Old 07-31-2010, 09:02 PM
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Originally Posted by geekhd View Post

Whether someone suggested or not, consumer cable termination products with silver plating are on the market.

Yes, and some people pay $1000 or more for an HDMI cable. Neither is necessary for a HDMI cable that performs flawlessly.
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Nobody is worried about the corrosion in the sealed environment of the inside of coax cable.

Aerospace and military equipment manufacturers certainly are concerned because it is not a sealed environment. The ends are open for one thing. Apparently you have never seen a coaxial cable where exterior connections were not properly weather proofed or the weather proofing failed.[/quote]
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post #30 of 48 Old 08-01-2010, 09:49 AM
 
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Who is going to peel back the insulation on the wire to look?

Why even bother asking? vvv
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Apparently you have never seen a coaxial cable where exterior connections were not properly weather proofed or the weather proofing failed.

Now you are talking about outdoor application?

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The ends are open for one thing.

It's "open" for sure. It's a non-issue once the plugs are installed at ends, especially for consumer use.
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