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I'm no expert, but I have soldered Kimber hook-up to Cardas copper posts recently. The one thing is, it takes a bit of time to get the post hot enough to melt the silver solder. Put the tip on the post and the wire and leave it there. I keep touching the solder to the post and the wire cause that helps to conduct the heat to the post. Once I see that the solder will melt on the post only, I go for it. I don't know what that sideways hole is for. I wanted the wires to come straight out of the post, so I didn't use it. One other thing....Cardas and some other wire, I assume, has a coating on it that must be removed before solder will stick to it. Otherwise the big thing is getting the post hot enough. If cardas solder is like Wunder solder, the flux is in it.
For those of you who may not know yet, brass is a relatively poor conductor. (Btw, do not use the brass jumpers if you are not bi-wiring, instead pull off the binding post cup and solder the wires to a single pair of BPs per speaker.) Spring for solid copper BPs with Rhodium or gold plating (not fake copper ones from Ebay) and make sure your spades are plated solid copper too. Rhodium is more durable, so I went with those because I figured I would be using these the rest of my life when switching between speakers over the years, keep the original hardware. (The same reason I sprung for the Furutech FP-201 spades in rhodium for my speaker cables)
I have 10 pairs of Cardas BPs and I originally had inserted the hookup wire into the BP’s cavity and filled it up with solder using a 60 watt iron. (Took lots of solder!) Sound was improved and I thought that it was the highest possible fidelity from my system. However, as time went by and I upgraded my system time and time again, I realized that solder is bad for sound because it is a poor conductor, excepting the silver, and there really is not all that much silver in the solder.
So I clipped off the hookup wires, got a Weller professional 300 watt gun, drilled holes in two pieces of oak scrap to clamp the BP in while I hit it with the Weller. The "old" solder poured out onto the tile floor.
I spoke to Cardas and this is how they told me to do it:
Using that same high wattage gun it was time to do this the right way:
Use some flux in the front portion of the BP’s hollow "tube" where there is more of a trough.
Tin the hookup wire and lay it in the trough.
Heat the assembly, then feed Cardas solder up through the little hole at the bottom of the trough. Use just enough solder to secure the hookup wire. Hold the hookup wire perfectly still. I
High watt solder gun heated the BPs so quickly that it was amazing how I could finish a solder even before the other end of the BP became all that hot.
Sound improvement was far beyond what I had expected!
"Solder should never be used to glue things together. The connection should be made physically sound first."
How do I make a solid connection to a Cardas binding post without using solder as the glue. It cannot be done because there are no set screws on a Cardas binding post.
This is why I do not like to post online because someone always comes along and thinks that I did it wrong. Do you think you know more than Sonic Craft and Cardas?
I have a high wattage iron I use mainly for Cardas binding posts. I think it is 80 watts but don't recall exactly. After the iron is fully heated up, I place the tip firmly against the outside of the post while the wire I intend to attach to it is resting in the opening of the post. (The wire is tinned in advance.). After 5 seconds or so, the interior of the post is hot enough that I can apply Cardas solder to the interior of the opening and it flows quickly and smoothly over the wire and along its sides where it is touching the post. I only use enough solder to coat the wire and have it join smoothly to the post. Then I quickly place the flat tip of a screwdriver on the wire and press it firmly against the wire and post while the solder cools. To be on the safe side, I leave the screwdriver there for 10 or 15 seconds until I am sure the joint is secure. The keys are to make sure there is a good mechanical connection, use enough heat, make sure the joint is fully heated up before solder is applied, and don't let anything move before the solder cools. Works every time.
"Use PLENTY of HEAT - we use TWO 35W soldering irons when soldering binding posts - and +1 to the comment above - there should first be a very solid electrical connection then apply solder to make it stick."
As I mentioned in my initial post per Cardas, I now use a 300 watt soldering iron with some flux paste in the binding post where the wire will lay. I can assure you that it is a night and day difference in both how the solder acts and it also results in a higher fidelity sound. I believe that this is why readers should not jump to a conclusion right away that results in them simply parroting what they have read before in other posts.