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Speaker Terminal Steel Is A Poor Conductor


mustang guy

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This was brought up in a thread in the 2 channel forum. I thought a discussion about it would be a good idea so we can clear the air.

I bought some cornscala D's about a month ago and I thought they sounded horrible. I messed with them night and day for 4 weeks. Luckily I stumbled upon something that happend to cure all of their problems. There was steel in the audio path. Both the screws on the terminal strips and the tabs that go from the crossover to the the terminal connectors were steel. I replaced the screws with brass ones and wired the crossover directly / bypassing the the terminals and now they sound insanely awesome.!!! I've included a picture to help illustrate what I'm saying. I'm not so sure about the screws but I replaced them anyways just to be sure, but the terminal strips were clearly steel that a magnet stuck to with great ease. Steel makes for a horrible metal for a signal to pass through and has almost 11 times the amount of resistance compared to copper.

Interesting. You made me look up the electrical conductivity of metals yet again. What I found is:

Brass IACS (% of copper conductivity)
Admiralty Brass 24.00
Admiralty Metal (Annealed) 24.60
Aluminum Brass (Annealed) 23.00
Cartridge (Annealed) 28.00
High Strength Yellow 12.00
Leaded Naval (Annealed) 26.00
Leaded Semi Red 18.00
Leaded Yellow 25.00
Low (Annealed) 32.00
Low Leaded (Annealed) 26.00
Naval (Annealed) 26.00
Red (Annealed) 37.00
Yellow (Annealed) 27.00
Aluminum Brass (Annealed) 23.00
Steel IACS (% of copper conductivity)
Steel, Cast 10.70
Steel, High Alloy 2.90
Steel, 304 Stainless 2.50
Steel, 304 Stainless 2.50
Steel, 347 Stainless 2.40
Zircaloy - 2.40
Steel, 316 Stainless 2.30
To summarize, most steel has a conductivity of under 3% of the copper wire you are connecting to it. Although brass is 10 times better, it is still about 1/4th as conductive as the speaker wire. Unless there are some physics I don't know about, this is going to impact current flow in a negative way.
On heritage networks, one could connect the speaker wire on the back terminal, thereby bypassing the terminal block. One could also run a jumper wire from the front to the back, which would serve the same purpose and allow use of the speaker input screw.
We need to hear from some people who have run tests on this subject. There is only 1 best way to do anything, and it seems like a steel terminal block is not the best way.
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Yes Brass and copper are very good and silver is the very best metal for electrical conductivity.

Many people think gold is good but it actually is not all that good for electrical conductivity, however gold does not tarnish easily so gold plating is used to protect electriical connectors from tarnishing since the connectors are usually made from metals that do have high electrical conductivity but also do tarnish very easily, usually brass, copper or silver

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Although steel has a high resistance relative to copper the distance the electrical current has to cover is small, so the cumulative resistance is low, hundredths of an ohm. The wires on many electronic components such as resistors, diodes, and transistors is tin or gold plated steel but the lead resistance is acceptably low over a 1/2 inch distance.

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one of the gotcha's that you run into when someone says going from steel to brass or gold to silver made an improvement is the unknown factor of what would have been the improvement if we would have went from steel to steel? why, no, not due to the placebo effect....but due to corrosion that is removed simply by removing and reinstalling the same steel part.....so obviously...installing a new steel part, gold or silver would appear to sound better. I like to use star lock washers under every single screw in the xover boards as well as the connection plates where screws, nuts and bolts are used.

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I would think copper to steel was a no no as far as dielectric corrosion was concerned.

Galvanic corrosion is a definite factor in the deterioration of connections. Here is a bit I picked up concerning reducing galvanic corrosion: "Choose metals that have similar electropotentials. The more closely matched the individual potentials, the lesser the potential difference and hence the lesser the galvanic current. Using the same metal for all construction is the most precise way of matching potentials." Also, electroplating with noble metals like gold, silver and nickel can reduce the corrosion. Zinc cannot be used because the zinc itself becomes the anode and corrodes.

Here is a table of electropotentials:

corrosion_corrosion.gif

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