Binding posts and metal conductivity?

vmaxer

F1nut wrote: »

Well, this got lively.

See what you started.

motorhead43026

codycatalist

motorhead43026 wrote: »

Pass that shizz

mhardy6647

I, in all seriousness, am out of my depth* when it comes to metallurgy.
_______________
* "Depth" -- Skin effect, plating... heh-heh-heh

DarqueKnight

Here is the response I received from Furutech::

My question:

"Your website states:

"The FP-803 features Alpha phosphor bronze conductors for minimal impedance and nonresonant matte black finished eutectic copper alloy housings."

Since phosphor bronze is 4.7 times less conductive than gold and 6.7 times less conductive than copper, I understand that conductivity of the bronze can be increased to equal that of copper or gold simply by increasing the size of the bronze. But then I would think there would be a problem with the larger amount of bronze having a detrimental effect on the sound quality of the binding post because most of the signal would go through the bronze base metal rather than the thin gold plating. How did Furutech address the issue of using a large amount of bronze without detrimental sonic effects?"

Furutech's response:

"Thank you for your interest in Furutech products.

Furutech tested numerous samples of phosphor bronze with varying percentages of tin and phosphor before deciding on the right mix for sound reproduction and use in their products. The phosphor bronze also under goes deep cryo treatment for improved conductivity.

Phosphor bronze is only used in the FP-803 post - all other Furutech posts are OFC grade copper or OCC wire. Please follow this link for other options: http://www.furutech.com/products/component-parts/binding-posts/

Hope that helps.

Kind regards,
Furutech Co., Ltd.
Tokyo"

F1nut

Ray, thanks for saving me the effort to contact Furutech. It seems they no longer offer the other models that used phosphor bronze, such as the 806 and 816. However, those models are still available from resellers and I was looking at the 806. Since they now only use it in their entry posts I have to think they figured out it wasn't the best idea after all.

DarqueKnight

xcapri79 wrote: »

I'm correct on all counts, no need to assume.

Please read the response from Furutech and explain how you can be correct on any counts when:

1. You don't know the conductivity of the phosphor bronze base metal compared to the gold plating. Furutech said they tried different formulations of phosphor bronze. These various formulations of phosphor bronze have different conductivities and sonic signatures.

2. You don't know the type and thickness of the gold plating and the thickness of the phosphor bronze base metal.

3. Since you don't know the relative conductivities and masses of the base metal and plating, you can't definitely say that most of the current goes through the base metal.

4. You don't know what other metals are used in the construction. For example, most gold plated binding posts are gold over brass, but the brass is first plated with nickel because gold does not adhere to brass very well. However, you seldom, if ever, see the nickel plating mentioned in marketing materials...only the gold. In the case of gold plated brass with nickel between the brass and gold, nickel is 21% less conductive than brass, so there is a further difference in conductivity between the gold contact surface and the substrate. Phosphor bronze is usually plated with a nickel substrate, but Furutech didn't specifically say. However, some type of substrate had to be used between the gold and the bronze.

If you have metallurgical and electrical performance data from Furutech pertaining to their phosphor bronze binding posts, please present it. Otherwise, you are just speculating.

gp4jesus

How about this BP base material comparison, again because some are discussing conductivity:
On the left, brass; on the right, phosphorus bronze. Left plug design provides more surface area, tighter fit, and plastic sleeves versus metal.

EndersShadow

This entire conversation and ALL the comments offend me.

Can we setup a Polk Audio "safe zone" so I can post in that section and cry and play with playdoh.

Sorry, dont really have anything meaningful to add besides "I agree with Ray"

mhardy6647

this should send all y'all scampering, whimpering & sobbing, to your safe zones.

DSC_6122 by Mark Hardy, on Flickr




EDIT: That's a very vintage JBL 275 1" compression driver mounted to an H5040 (right angle) "Metregon"-style treble horn, by the way.

K_M

O.C.D. and caffeine do not make a good match.

Think we can all agree on that....

Nightfall

mhardy6647 wrote: »

this should send all y'all scampering, whimpering & sobbing, to your safe zones.

Noooooo! I hope those 5 cent spades and alligator clips are at least cryo treated, tell me they're at least cryo treated!?

mhardy6647

I put the wires in the ol' Kelvinator for a while before hookin' 'em up

daddyjt

EndersShadow wrote: »

This entire conversation and ALL the comments offend me.

Can we setup a Polk Audio "safe zone" so I can post in that section and cry and play with playdoh.

Sorry, dont really have anything meaningful to add besides "I agree with Ray"

There... I ALMOST posted it with a straight face...

lightman1

You're fired, Hardy.....twice.