New To Mac Mini - External Speakers

McBlob - thanks for the swift reply - still nothing happening - the speakers work fine if connected back to my old Dell. When connected the my Mac Mini I'm unable to fined them anywhere in Sounds or AudioMIDI set up - only the internal speaker is showing?

When I was disconnecting the jack plug the speakers made a brief boom noise (very loud as I had the volume turned high) but that's the only sound they have made when connected to the Mini?

Any ideas....

Yes I have tried rebooting a number of times with power on/off to the speakers and connected/not connected - unfortunately still no sound or showing in the Sounds section?

Yes I have also double checked that, after your suggestion and the plug is right in up the the raised shoulder at it's base.

I saw a post somewhere that the plug should have a number of sections (seperated by rubber rings) would that make any difference, as my Dell one is a solid unit with no seperated sections?

The plug on my Dell A525 speakers doesn't have the black rubber sections?

I have tried an adaper 3.5 - 3.5mm that had the two rubber sections and that also didn't work unfortunately......

I don't have any other speakers but when they are plugged back in to the Dell they work fine?

I have headphones and earbuds from my iPod - I'll try them - thank you for the suggestion?

Good news a friend gave me another adapter and I'm up and running *** how, who, what and why I have no idea - but I'd like to say thank you for all your help, ideas and suggestions etc....