Gold and audio

[PhilGood]

I know this probably shouldn't be in the mic forum. I just trust the pros who post here and wanted to ask.

I just read an interesting article having to do with the conductivity of different metals and audio signals. Silver is the best metal for audio cables, because it can handle all the information well, as well as low oxygen copper or oxygen free copper. Silver plated copper, however causes a harshness.

Here's the interesting part. The author said that despite the equipment being sold out there to ensure quality audio, gold is a poor conductor for audio. Another engineer had told me a week ago that having a gold connector touch a nickel connecter altered the sound. This may be why. Gold apparently is neither low-distortion, nor low resistance. It can't carry all the data well.

Anyone have any professional opinions contrary or otherwise?

[baekgaard]

Apart from the obvious marketing value: "the more expensive it sounds the better", the reason gold is being used on connectors is that it is pretty stable and does not corrode/oxidize as easily as other metals.

An oxid layer (i.e. what is equivalent to "rust") sometimes behaves a bit like a semiconductor, and that can introduce distortion. If it is really bad, it may mean that you start hearing the nearest long-wave radio in your microphone... Thus, by using gold plated connectors, the risk that this happens, is somewhat less.

It is, however, not a good idea to have two different metals sitting next to each other, since there will be a metal potential difference between them (like in a battery) and they may start exchanging ions and create a similar kind of distortion as above. This is why it is a bad idea to use e.g. gold plated memory cards in a nickel slot in your PC.

For audio, it is obviously similar, although often the cables only have shortlived contact (i.e. you remove them after use), and hence the risk is less.

Thus: If you use gold plated connectors on your cables (of a good quality) they may last a bit longer before they corrode/oxidize. If they are of low quality, the gold plating will just come off shortly after taken into use.

If you mix them with non gold plated connectors, there is a minimal risk of introducing a slight amount of distortion between the different types of metal where they are in direct contact with each other. Thus, in your home stereo, just use the same type of connectors everywhere. In most other applications, there will be no audio impact when both connectors are new and clean. More important issues are that the connectors are of good mechanical construction and lasts years of use, without the plating coming off or the cables getting loose.

What you said about the reason for not using gold-nickel contact is as above, and has nothing to do with golds resistance. Also, gold by itself does not cause any distortion; only when you have two different metal transmitting electrical signals to one another.

As for the sound: Usually, other factors have at least a 10 fold larger impact on the sound, including also placement of speakers (in your home stereo, where this discussions usually appear).

YMMV,


-- Per.

[PhilGood]

Now THAT's a good explanation!! Thank you!!

The potential between two metals...hmmm. I know about gold being a 'noble' metal, in that it doesn't corode, but two metals touching... that's good to know! So, gold is good if it's gold against gold, but not against nickel. Great!

You all may continue about your business!

[Be Loveless]

Someone finally laid out this issue concisely. GREAT JOB!!! Been curious about this myself. You get a rep point.

[paddyponchero]

Originally Posted by baekgaard

As for the sound: Usually, other factors have at least a 10 fold larger impact on the sound, including also placement of speakers (in your home stereo, where this discussions usually appear)

There is 0.3V difference in the anodic index between gold and nickel

Far more importantly there is also 0.3V difference between copper and tin-lead solder and 0.35V difference between nickel and tin-lead solder.

If nickel-gold contact produced any kind of measurable distortion how do you think all the solder contacts in your equipment would add up.

And thats not even mentioning the aluminium-gold, copper-gold, nickel-gold, nickel-copper connections existing in the components.

There would not even be a way to measure such 'distortion'

As for 10 fold larger impact, 10 fold is 20dB which I'm sure you'll agree anyone could hear, 10,000,000 fold larger impact is still only 70dB which most people could also hear on appropriate equipment.

[apl]

It's just silly but it makes money.

[gemsbok]

my local shop about 20 years ago told me that brass was a great metal for guitar cable ends but it has to be cleaned all the time. does brass out preform nickle?

[mshilarious]

Be very, very wary of using audiophile sources for information. If they can't back up their subjective observations with hard science, keep moving. Listen to paddyponchero on this one. Gold is used because it doesn't oxidize. So you can use gold, or you can clean your connectors with DeOxit every couple of years, it really doesn't matter.

Anyway the gold is just a thin plating, which is why you'll see it on home audio connectors but not too many pro audio connectors--plug the cable in & out a few times, and the gold starts to wear off.

[baekgaard]

Originally Posted by paddyponchero

Far more importantly there is also 0.3V difference between copper and tin-lead solder and 0.35V difference between nickel and tin-lead solder.

If nickel-gold contact produced any kind of measurable distortion how do you think all the solder contacts in your equipment would add up.

Not sure if you intended to argue agaist what I said above or to support it, but I choose the latter -- i.e. that we basically agree that there are more important things to sound than theoretical metallurgical problems ;-)

Anyway, I know I simplified matters above, since I'm not a metallurgical specialist. But I think the main difference between a contact point in a connector and a solder point is the presence of an electrolytic substance (humid air, containing water) in the former vs. an alloy and intermetallic layers being created in the solder points -- i.e. soldering is a metallurgical joining of two items. The flux used in solder is used to prevent the building up of oxides between the solder and the surfaces and to help on the "wetting" process, allowing the solder alloy to float/wet the surfaces.

If a solder point is not done correctly (typically because the parts being soldered are not heated well enough), you get what is often called a "cold solder joint", where parts have not formed an alloy or there are bigger lumps and crystals forming in the allow. Such a solder joint may, after some time of exposure to humidity in the air and possibly mechanical stress due to heating/cooling, start behaving like a semiconductor or a resistor. It may be the source of the radio that you start hearing in your preamp, although most often it just increases noise and eventually causes a complete malfunction.

For older equipment, a "standard" treatment I learned many years ago to fix intermittent problems or noise can be to re-heat all joints, just to ensure that there is good contact. Sometimes it actually works...

Originally Posted by paddyponchero

And thats not even mentioning the aluminium-gold, copper-gold, nickel-gold, nickel-copper connections existing in the components.

All these are also alloys, such as the bonding of gold wires onto the substrate/interposer or the die in the IC's, etc.

Originally Posted by paddyponchero

As for 10 fold larger impact, 10 fold is 20dB which...

Sorry, 10-fold was just a figure of speech, not to be interpreted literally. I meant to say you should spend 10 times more energy thinking about other factors than about metallurgical problems. Probably a language thing (I'm not native english).

So... my bottom line is, that yes, there can be problems stemming from the use of different metals (and I tried to explain why, somewhat simplified), but in practice other issues are far more important.

And I guess that is what you meant also?




-- Per.

[baekgaard]

Originally Posted by mshilarious

Listen to paddyponchero on this one. Gold is used because it doesn't oxidize.

Just for the record, I think that was what I said, not what paddy said -- although I'm sure he agrees ;-)


-- Per.

[paddyponchero]

Originally Posted by baekgaard

So... my bottom line is, that yes, there can be problems stemming from the use of different metals (and I tried to explain why, somewhat simplified), but in practice other issues are far more important.

And I guess that is what you meant also?




-- Per.

Sorry Per, yes thats what I meant, just got a bit carried away - it's a bit of a hobby horse of mine.

[baekgaard]

Originally Posted by paddyponchero

...

-- Per.

[cellardweller]

So gold is slightly (though insignificantly) more conductive, wears away quickly through normal use, and is much more expensive.

Am I inferring too much from the above, or are gold connectors not really worth the extra $ then?

[baekgaard]

Originally Posted by cellardweller

Am I inferring too much from the above, or are gold connectors not really worth the extra $ then?

I don't buy gold connectors for audio myself... and I strongly suspect Paddy also doesn't...

YMMV. It's your money, after all ;-)


-- Per.

[bennychico11]

interesting topic....props for the info