Brass versus copper binding posts

Typically, connectors and such will be made with one of the brass/copper alloys commonly used for electrical connections. Tellurium copper is a common choice or Muntz Metal, other alloys may be used for cost saving factors. After machining they will be copper flash plated, then finished plated with gold, silver, or other finishes. The plating is going to carry the electrical current so except for wear just about anything will work, even steel. 

@milkdudd ,

I have those same speakers. Never considered changing binding posts, they are so hefty and nicely made. I can recommended bi-wiring however. Of course low mass is all the rage these days 

I think copper is the most conductive but it can rust or oxidize over time.  I think that is why they do bronze or rhodium or light gold plate, to make sure there isn't rust over time.

Silver has lower resistance than copper or gold.

A good red copper with a silverplating is a concept for connectors. 

Skip the rhodmium.

Copper doesn't rust.

True, copper doesn't rust, but it does corrode.

Sorry I meant corrosion not rust.  Poor choice of words on my part.  I haven't seen speakers with silver binding posts though but maybe those are well above my pay grade so to speak.

I used Pomona Electronics Gold plated Tellurium copper binding posts ages ago and they were very good (compared to running the speaker cable directly to my single driver speakers).

They weren't beefy (but still sturdy) and I prefer less metal mass in connectors.

DeKay

I prefer solid copper binding post with heavy silver plating to prevent corrosion. See below:

Mike

ETI Research KRYO Binding Post

ETI KRYO Binding Post - $149.00 (single pair) Enter Quantity --->>

The ETI Research Kryo Binding Post is like no other on the market today. The conductor is made from Silver-Plated Tellurium Copper for not only superior conductivity but long-lasting durability. ETI believes this is the most transparent sounding binding post on the market today. CONDUCTOR: Silver Plated Tellurium Copper. HOUSING: Brass (Black Finish). Sold as ONE PAIR (1 red and 1 white post). If purchasing for a stereo amplifier or stereo pair of speakers, you will need FOUR posts (two pairs). Each pair contains one white, and one red color coded post.

Thanks again for all the help everybody. I contacted Usher in Taiwan and they emailed me that yes the binding posts are brass. The ETI items shown above were actually my first choice. I use their XLR connectors from the same family on my interconnects. Being that I would need four sets ends up to $600 to make the change that’s a lot of money. I have found a company named AECO in Taiwan that makes a similar binding posts for $60 a pair rather than $150. Model number ABI-0611 followed by a suffix of G, S or R that designates gold, silver or rhodium plating directly onto tellurium copper. All of my speaker cables are Clear Day silver with silver plated spades and bananas. So I think I will be ordering the silver plated versions.

Those connectors are very good. The KELI connectors are very good also.

@ditusa,

Silver does not prevent corrosion. In fact the silver surface is fairly reactive and can corrode fairly rapidly depending on the number of silver atoms on the surface that are not fully coordinated. Unlike copper which oxidizes to the +1 oxide (Cu2O) and +2 oxide (CuO), silver does not readily form oxides. Instead silver readily forms a sulfide (Ag2S). Both silver sulfide and the oxides of copper are semiconductors with similar band gaps.

Ah, those darn connectors.  Seems there is no perfect solution.  Gold and Rhodium don't oxidize, but they are not very good conductors.  I had an silver plated AQ rca plug that literally turned black.  That can't be good.  

Here is another fact to drive ones OCD nuts.  Just read how tin plated conductors react with gold.  So that is another often ignored no-no. 

How about low mass copper to copper treated with ProGold?

In the end, it will be a compromise like most things in life.

@ljgerens Wrote:

Silver does not prevent corrosion.

The company below disagrees:

Mike

https://www.ganpatiengineering.com/silver-coated-copper-wire-round.html

@ditusa,

Ok, I should have stated that a silver coating will prevent the underlying copper from corroding, but silver itself corrodes. The company you quoted does say they apply an enamel coating over the silver, which would prevent corrosion.

I studied the surface chemistry of silver for several years and I can unequivocally state that silver surfaces corrode fairly rapidly on exposure to the atmosphere. The primary corrosion species on silver are sulfur and sulfur containing compounds. Other corrosion species that I have found on silver surfaces include chlorine (Cl) and carbonates (CO3).

@ljgerens,

Thank you for the explanation. 😎

Mike