Dead Speaker

[newfish]

Hi All,

I recently put a switching socket on the speaker wire of a small amp.

Existing wires now go to one side of the socket with the speaker connected to the other 2 - so that with no external jack plugged in, the output goes to the amp's internal speaker.

Plugging a jack into the socket diverts output to the jack plug - and nothing to the internal speaker.

All is well and good, but the internal speaker has now given up - a DMM across the speaker's connectors gives an 'open circuit' reading instead of the 4Ohm stated on the back of the driver.

Output through an external cab is as good as ever.

The switching arrangement was in place for a few days - and worked very well.

I'm now wondering if there was anything I could have done to cause the speaker to give up.

...and yes, I was mindful of the impedance of the external speaker I plugged in.

Speaker switching is always carried out with the amp switched off.

Is this simply a case of 'your speaker died because it was worn out' ?

I'm mindful that speakers *do* give up eventually (although the combo is only 5 years old...)

Would someone please help me put my mind to rest?

[petemoore]

  Ya never really know.
  I didn't read anything in there that sounded like...for frying a speaker.
  A check I like to make is the '9v-click' test, briefly touching a 1/2 dead or 9V battery across the speaker connections, the speaker should 'say' 'KLIK - Ko' [the cone moves in or out while the DC across the coil pushes it that way]..quick dirty and very effective test of speaker coil continuity.
  Be mindful I don't think you can hurt anything that'd normally be connected to the speaker, mind that or disconnect the speaker before '9v-click-testing' it.
  Modern instrument speakers tend to be able to take lots of 'abuse', generally 'crying' for a time [or making one really really loud POP] before giving up the coil.
 
 

[Albot]

Doesent sound like anything dramatic hapened to the speaker.
If you did do any soldering on the internal speaker you should check if the speaker wires from inside the cone are still connected to the terminals. I've always been amazed they never seem to come off when i solder them and they might be something you don't think very much about and it's bound to happen to someone.
Maybe a cold solder joint that let go after a while or something..

If that's not it try to meassure resistance instead of continuity.. might be something with the inductance messing the continuity test up.
I usually get very close to the specified impedance with resistance meassurements, I'm no expert though.

Good luck

[newfish]

Thanks Guys.

I didn't touch any of the wires directly on the back of the speaker.

Also refreshed all my solder joints - just in case.

Still no joy.

Oh well...  S**t happens.

[earthtonesaudio]

Speakers are pretty tough, and if you didn't see smoke and flames coming out of the thing, chances are it's still good.  More likely is there's a problem with the modification you installed.  Connections have to be mechanically good in order to be electrically reliable.

Try this: disconnect the speaker from everything else and measure it's resistance.  If it's still an open circuit, the speaker is indeed damaged.  If it reads 4 ohms, it's probably still good and you should go back over your wiring.

[newfish]

Smoke and Flames?  <eek!>

I thought I had made things mechanically sound (solder isn't glue etc...)

However - I'll gladly take your advice and re-check with the speaker disconnected.

Thanks once again.