Vintage speaker restoration. A soldering question.

[Kuja]

Hi!

I'm restoring a pair of Acoustic Research AR-90 speakers.

I just finished the crossovers.
There is no PCB. They are made using direct point to point soldering of components.

I have new caps, wiring and speaker binding posts.

At one point I got stuck when I had to solder two bundles of thick solid core wires to the 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.

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 this sketch you can see that 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.


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,

Aleksandar

 

[j_garcia]

That is a pretty ugly looking glob of solder. Yes, I do think a bad solder joint could cause some ssues, but in the grand scheme of things, I wouldn't expect it to be immediately audible.

 

[Swerd]

Even though it looks ugly, as long as electrical contact remains intact, I doubt if you could hear any difference. From your photos, it looks like nothing can move or flex in that joint that might weaken a cold solder joint.

As your pictures and diagrams nicely show, you now have learned a method that seemed good in theory but you definitely don't want to repeat.

Next time you try this, instead of using a hotter iron, don’t bother using solid core wire. It is too hard to work with. For internal wiring, I use 16 gauge stranded wire. Anything thicker is too difficult to work with.

You are right to suspect all that “crystal or submolecular metal structures” talk as audiophool nonsense. What kind of wire was originally used in the crossover?

So after you assembled it, how did it sound to you?