Dave :
It unfortunately depends on your car stereo. All of the standard
headphone jacks (and AFAIK headphones) assume a common ground for both
channels. However, although a common ground is found on many cheaper
car stereos, quite a few higher end units do not use a common ground,
and will self-destruct if you connect the - leads together. Read the
installation instructions for your new stereo (if you have them), and
look for cautions not to connect speaker leads together. Since the
plugs are typically standard for a particular mfgr, the plug itself will
have separate wires. If the leads are common, they will be connected
inside the unit.
The safe way is to use the "-" lead from only one channel as the common,
but that may make the other channel sound funny in the headphones.
Note that it's best not to make a connection to chassis ground at the
jack. Doing so may introduce noise and/or DC into your headphones.
You may also want to consider providing a disconnect for the main
speakers (you can get jacks with this built-in, for reasonable power
levels), since a comfortable listening level on the headphones may be
rather loud through the speakers.
ISTR that the tip is the RH signal, and ring is the LH signal, but I
could be wrong. The body (behind the ring) is definitely the common
connection.
Randall
dstauffa@csc.com wrote:
>
> The each speaker wire has a + and - lead. Do the ground leads share the same
> tab on the stereo plug?
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