Blown Speaker? No, Oxidized terminals.

[fieldcar]

Hello friends. I just wanted to fill you in on a surprising thing I noticed when breaking out some old JBL N26ii's from my attic. I thought for sure that I had a blown woofer as I was getting distortion on a single speaker. I was mentally preparing to toss the "old and worn out speakers", but after bypassing the crossover, I found that the woofer was in perfect condition, so the next thought was that the crossover had aged poorly, but no caps were bulging or leaking. After reconnecting the woofer to the quick-disconnect terminals, it was back to normal. It's crazy how a little bit of oxidation sounds like a blown speaker.

So, let me know, have you experienced this? Did you toss any "blown" speakers without checking this?

 

[fpitas]

Oxidation makes metal oxides, which are often semiconductors. So you get a non-linear contact, and distortion. It can also happen on the back of the speaker, with banana plugs or, especially, wires shoved through binding posts.

You might want to use a little dielectric grease when you re-assemble, to keep the moisture out.

 

[Joe Smith]

Very good to know, thanks for posting. Have not experienced this but I have a lot of vintage speakers that I rotate through, so will watch for this.

 

[bigjacko]

Oh, nice save! What do you mean by reconnecting the termnal? Was the terminal lose or you crimp a new terminal on? I am wondering how safe it is to use faston terminals on drivers, since drivers have vibration. Is it good to use faston as is or add some other stuff to make them not fall off?

 

[fpitas]

Be very careful if you solder, not to melt the existing connection.

 

[Thomas savage]

Just regluedy vivid g3s , the sunlight had eaten all the glue stick from the bass driver .

Sunlight is a bitch ha ha

 

[Katji]

That's odd, considering the amount of sun here. Although not many sold here.

 

[fieldcar]

Oxidation makes metal oxides, which are often semiconductors. So you get a non-linear contact, and distortion. It can also happen on the back of the speaker, with banana plugs or, especially, wires shoved through binding posts.

You might want to use a little dielectric grease when you re-assemble, to keep the moisture out.

Definitely. I had a fun experience with some cheap-o amazon basics banana connectors that spun freely, barely making contact.

As long as they don't go back into the attic, I think I'll be OK, but thanks for the suggestion.

Oh, nice save! What do you mean by reconnecting the termnal? Was the terminal lose or you crimp a new terminal on?

I suspect that the oxidation between the plates of the male and female connectors were oxidized, so it was a poor connection. The friction of reconnecting them probably removed the oxidation. Your post does make me wonder if the crimp on connection to the wire is still good. Though, they usually tin the wire before crimping to prevent oxidation and corrosion.

I am wondering how safe it is to use faston terminals on drivers, since drivers have vibration. Is it good to use faston as is or add some other stuff to make them not fall off?

These connectors (quick-disconnect, not spade, whoops) were JBL's choice from the factory. They now use locking connectors in the 500 series speakers that work pretty well.