I forget what they're called, but you'll need a switched jack, actually 
it would have 5 terminals.  Ground and left and right hot which is what 
would contact the left and right on the headphone plug.  Fourth and 
fifth terminals go to each speaker and are connected when the plug is 
removed.  This would only work if the speakers share a common ground 
which isn'
t always true particularly with output ics used these days.
73
Butch Bussen
wa0vjr
open Node 3148
Las Vegas


On Sun, 19 
Jul 2009, Mark wrote:

> Hi
>     I am trying to wire an earphone jack in to a stereo that has only =
> built in speakers. I bought a "stereo Jack" from radio shack. The =
> trouble is there are only three contacts on the jack. I am guessing =
> left, right, and ground. How do I get the audio to switch back to the =
> speakers when the earphone plug is removed from the jack?
>     Any help is appreciated.
>
> God bless,
> Mark
> --=20
>      Currently in Pendleton, Eastern Oregon Regional At Pendleton, =
> Oregon Clear, 84.0=B0F Wind:WSW-250=B0 at 9mph
>      Stewardesses is the longest word that is typed with only the left =
> hand.
>      Created by Weather Signature v1.20 =95 http://www.weathersig.com
>      God loves you!
>      http://www.arrl.org
>      www.donorschoose.org
>    =20
>
>