Replacing jack socket on guitar cab

ten77guitar

Hoping I’ve posted this in the right section and it may be a stupid question but if I replace the jack socket on a guitar speaker cabinet can I use any standard jack socket, i.e. the same as you would use on a guitar?  The cab has stopped working so I tested the speaker with a multimeter and it seems to be okay. I also re-soldered the leads but no joy so I’m thinking  there must be an issue with the socket itself?

mrkb

Have you tested the lead with a multimeter?

@icmb seems knowledgeable on this kind of stuff. What wattage is the speaker/amp?

ICBM

Check with a multimeter from the end of a cable plugged into it to the speaker itself and find where the break is. Although it could be the jack, it's not that likely.

If it is the jack, replace it with the same type - if it's one like this
 
then it's best to use one, not a guitar jack.

ten77guitar

mrkb said:

Have you tested the lead with a multimeter?

@icmb seems knowledgeable on this kind of stuff. What wattage is the speaker/amp?

Thanks for reply. Haven’t tested the wires as there is no obvious wear on them but will try that before I replace the jack. Is there a way of testing the jack itself?

The amp is 20W going into a 400W EVM speaker! 

ten77guitar

ICBM said:

Check with a multimeter from the end of a cable plugged into it to the speaker itself and find where the break is. Although it could be the jack, it's not that likely.

If it is the jack, replace it with the same type - if it's one like this
 
then it's best to use one, not a guitar jack.

Okay thanks. The second part of your answer I understand - and yes it is one of those types.

The first part I’m struggling with a bit (I am that dumb!) Are you saying I should plug in a lead and test one probe against that then the other probe at the speaker terminal? 

ICBM

ten77guitar said:

The first part I’m struggling with a bit (I am that dumb!) Are you saying I should plug in a lead and test one probe against that then the other probe at the speaker terminal?

Yes. Follow the signal path from the tip of the plug to the speaker - you can just use the beep test if the meter has that - and from the sleeve of the jack to the other terminal. That should show you where the break is - eg if you get a beep between the plug tip and the contact on the jack, but then none at the speaker, it's the wire in the cab not the jack.

ten77guitar

Thanks again ICBM. It seems you
were right about the jack - it tested fine and so did the wires so it must be the speaker. I tested it again with the multimeter and there is no reading. However, if I swap the probes round - so they don’t match - I get a reading of 15ohms. Does that sound right? This must be the reason I thought it was okay when I first tested it. I also tried testing with a 9v battery and no result.

I thought EVMs were supposed to be virtually indestructible?  The cab stopped working after I took it somewhere in the car so there would have been some movement and vibration but it wasn’t dropped or anything like that. 

ICBM

Is it one with the spring terminals? Those can sometimes cause trouble.

Disconnect the speaker and very carefully meter it by putting the probes onto the cone braids themselves - be careful not to tug on them. If you get a good reading there (6-7 ohms for an 8-ohm speaker, or 12-14 ohms for a 16) then it sounds like a connector problem.

If that's still no good it is also possible that there could be a manufacturing fault in the voice coil - very rare, but it can happen, probably even on an EV.

ten77guitar

Thanks, just tried as you suggested - nada. A trip down the council waste centre tomorrow then?

ICBM

ten77guitar said:

Thanks, just tried as you suggested - nada. A trip down the council waste centre tomorrow then?

No, an EV is valuable enough to be worth re-coning.

ten77guitar

Great, that’s good to hear! Thanks for all the advice.