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AR-90 restoration... A question regarding soldering.


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Hello again! :)

My restoration of AR-90s is almost over.

It's time to put the crossovers in the cabinets.

But there is one thing that worries me...

At one point during crossover rebuilding, I got stuck when I had to solder two bundles of thick solid core wires to new speaker binding posts.

My soldering iron was not powerful enough. It couldn't provide enough heat, so I was not able to do everything in one go.

I was kind of building up things by adding solder partially to different spots. Finally, I ended up "sculpting" solder with my iron.

These are the binding posts in question:


New internal wiring is solid core 14 and 16 AWG Neotech UPOCC (monocrystal copper) wire.

Here is the result.


It looks kind of ugly, but I can assure you that everything is rock solid and that there are no cold solder joints.

My question is:

Are there any sonic penalties that can be heard with such a bulky solder joint in a speaker crossover?

I hope that I'm fine and that it won't sound worse compared to some nicer looking solder joints, but who knows?! I'm not an expert on these things.

On the internet, I can read a lot of audiophool voodoo stuff.

Some of it regarding crystal or submolecular metal structures and things like that.

In that light, those solder joints look really bad! :(

So, am I going to be able to hear it or not?

What do you think?

Thanks in advance,


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IMO you don't have anything to worry about. However, you could have used a simple terminal strip and run 1 wire from your WBT input connector to an interonnected 3 or 4 gang terminal strip and then attached each of the other black wires to separate terminals. With all the solid wires connected together like shown in your picture, you had a huge mass to try and heat up. Doing only 1 wire at a time would have solved that problem.

In any case you seem to have done a good job.

Speaking of audiophool voodoo stuff, I read a Wilson Audio (mfg. of the infamous Wilson Watt Puppy) ad that said they use different solders in different areas of their crossovers to optimize performance. I LOL at that one.

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In any case you seem to have done a good job.

Speaking of audiophool voodoo stuff, I read a Wilson Audio (mfg. of the infamous Wilson Watt Puppy) ad that said they use different solders in different areas of their crossovers to optimize performance. I LOL at that one.

Oh, thats a Hoot; Different solder for different sounds. The only way that might work is if some of the joints were bad. My father taught me over 40 years ago to make strong mechanical wire connections and depend on the solder to only hold the wires together, not to conduct. In a nutshell, use a wire nut, use solder, or whatever you want. make a sound mechanical connection and it's connected for life.

These solder joints might just be an original work of art given what's considered art today.

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Congratulations on nearing the completion of your project!

Audiophile nonsense aside, good connections & proper soldering are crucial to the performance & reliability of your speakers.

Building up solder onto a joint isn't really considered proper technique.

You must first have a solid mechanical connection, and then properly flow solder into that heated joint.

I'm afraid that your iron isn't up to the task, and that for the best result, you'll need a heavier-wattage model.

It's a small expense to do it right, and you'll feel much better afterward - really!

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Audiophile nonesense aside, there are significant differences in solders and the choice of which is best used to connect specific metal pairs.

The traditional tin-lead eutectic solder that I first used as a kid sixty years ago still works well for copper, nickel-plated copper, tin-plated copper and the like. You will not find it used in commercial electronics today for environmental reasons - elimination of PbO vapors from the workplace and Pb from recycled circuits. But it still solders copper today just as well as it did a hundred years ago!

A look in an electronics store will reveal several non-lead bearing solders (tin, antimony, silver, etc) whose existence is owed to environmental concerns. If lead vapors are a concern (working around young children, and so on) then use one of these lead-free formulations.

Another alloy contains 62% tin, 34-36% lead and 4-2% silver. This, or other alloys containing silver, are needed only if you are soldering joints containing silver plated wire. Let's not get into the audiophile argument that you can hear the difference :-) Lets just stick to the tin/silver phase diagram. If traditional Pb-Sn solder is used to join silver plated copper wire, the silver plating will diffuse into the tin to a concentration of about 2%. (The solid solubility of silver in tin.) If the silver plating diffuses into the tin, it leaves a void between the copper and solder, and can result over long times in a high resistance joint. So by the simple means of doping the tin to about 4% silver (making it a supersaturated solid solution) the silver plating cannot move. The joint's low resistance will not change.

So the audiophile advert that claims "different solders were used in different areas to optimize performance" may be precisely correct. However, that begs the question - did that audiophile circuit ever need silver plated wire in the first place!! One could say the advert is technically correct, but built on a false premise. I've not found silver plated wire necessary, has anyone else?

I do agree with other coments here: solder is for electrical conduction, not mechanical connection! That is one function of a tie point, or connector strip.


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Re audophile wire/solder/whatever...

McIntosh Labs, in their amplifier clinics many years ago proved that there was NO benefit to "fancy" wire. The only thing that mattered was that the wire be of sufficient gauge for the run between the amps and speakers. Standard zip cord sounded exactly the same as the expensive stuff. I was a fanatic audiophile during the 60's 70's 80's and did my best to spend every dime I had on the latest and greatest stuff. I REALLY TRIED to hear a difference in wire because I WANTED there to be a difference so I could spend a thousand dollars on wire and be the envy of everyone on my block. But there wasn't (and isn't) any difference; zip cord in the proper gauge does the job as well. McIntosh proved/demonstrated it but no one wanted to hear it, especially the people marketing the various "magic" wires! :(

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Thank you all for your valuable answers!

I made this sketch to to explain better what I've actually done here:


Before doing any soldering, I tried to make a good mechanical connection between the wires and the speaker binding post lug on their own, without any solder.

On the sketch you can see that this lug has a hole, so I had one wire going through it to the other side, where it made a loop around twisted bundle of other wires and then it went back.

After looping and tying the wires and the lug together, I squeezed everything together with pliers.

Only after that I started soldering.

Does this additional explanation makes those joints look better? :(

I hope so, since it would be a hell of a job to take everything apart, since I already poured a ton of hot melt glue over all joints and capacitors to prevent them from vibrating too much.

Thanks again!

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Does this additional explanation makes those joints look better? :(

Well, no, they don't *look* any better. But they'll probably work

fine and who's going to see them once the box is closed up.

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