solder or spade?

[Moondog55]

When you talk about high power what voltage & amperage are you talking about??
I was under the impression that crimping was only done because it is almost impossible to solder anything over 6mm*2
Unless you have access to hydraulic crimpers is it possible to do a good crimping job??

I use solder to ensure a pre-crimped connection can't vibrate off the tag and some rally engineers I have known do the same thing ( actually that's where I first encountered the practice )

[SpeakerScott]

Originally posted by Moondog55
When you talk about high power what voltage & amperage are you talking about??
I was under the impression that crimping was only done because it is almost impossible to solder anything over 6mm*2
Unless you have access to hydraulic crimpers is it possible to do a good crimping job??

I use solder to ensure a pre-crimped connection can't vibrate off the tag and some rally engineers I have known do the same thing ( actually that's where I first encountered the practice )

The problem is multi-fold.

1. Most crimp connections are designed to place a certain amount of pressure, over a certain amount of area, if you solder before crimping the wire can't spread out correctly and the crimp won't have the correct shape and the correct clamping force.

2. When soldering after a crimp, the solder travels unevenly up the strands of the wire, creating uneven application of force if the wire is flexed at the crimp/solder point. Individual strands will break before he others, and the failure point is inevitably the solder joint end...I've seen this in person, in the project I first did as an engineer.

I've seen very large cables crimped, and I've seen crimpers that look more like bolt cutters, with 3' handles. Proper crimping pressure is what's needed.... One MIL-SPEC project I worked on required that every crimp was pull tested before inserting into the system. Dang that was a pain in the gluteous maximus. The paperwork alone was a nightmare.

Scott

[infinia]

Originally posted by Moondog55
When you talk about high power what voltage & amperage are you talking about??

Big stuff.. powerline XFMRs 480V/200A and welding cables, thats where you need to know what you are doing or .
But the technology should work for low power as well.

That's where most of the probs I've seen are at the spade end not the crimp itself. If you solder just the wires, you can use less heat at the tweeter terminals and eliminate one connection out of two.

[HK26147]

To prevent/contain heat spread and damage use mini alligator clips and hemostats as heatsinks.
With good solder & pre-cleaned/ tinned surfaces, I haven't had a cold joint problem or heat damage.
( I also like to use a liquid flux in a syringe applicator ).
I strongly prefer solder connections ( unless the driver comes with good spring connectors ).
In subdued lighting I have seen "microarching" between 1/4" spade lugs and tabs, with pitting on the metal contact surface.

[Pano]

Hmmm........ So you guys think that soldering a crimped spade is not a good idea? It works well for me.

Certainly I've done many 1000s of crimp connections - mostly BNC or F connectors on coax - and they worked fine. But with rough treatment they often break. (Not saying they'd get rough treatment in a speaker).

The typical crimps I've seen on small gauge spades has not impressed me. That's why I solder, too.
But hey, I'm willing to learn a better way.


FWIW, I don't solder to drivers.