Mark writes:
>      I hope that the adapters I bought from radio shack will have the 
> right
> components built in. Now, I am worried.

	A male stereo headphone plug has 3 connections. Starting
from the handle of the plug, there is the sleeve which is the
common ground for the other 2 connections. As you go down the
sleeve, you encounter the Ring and finally the Tip. The Tip is
usually the left channel. The Ring is usually the right. If you
insert a mono headphone plug in to the jack, you will short the
right channel to ground which is not what you want to do.

	If you have an adaptor that connects the tip and ring
together, you are shorting the left and right channels together
which is also not what you want to do.

	To combine the left and right channels without smoking
the amplifiers, you want the left and right channels to not be
directly connected.

	I don't know what you have there so I can't guess, but
most of thos adaptors do not contain any resistors because the
resistors would need to be different values for different
applications.

	I think the safest thing to do is build an external box
containing the right sized resistors and the appropriate jack
for the mono headphones.

	Some ham gear such as a number of Icoms will take either
a stereo or mono headphone plug. the way they do that magic is
to install a stereo jack and solder a resistor in series with
both the left and right channels. If someone plugs in a mono
plug and shorts the right channel to ground, it is okay and
nothing bad happens.
	
If you did that on your computer sound card, you might just blow
the output of the D/A converter and, if it is on the mother
board, you have wrecked the mother board so that is why you need
to be sure you aren't stressing the amplifier.

	It is amazing how cowardly I have gotten as I get older.

Martin McCormick WB5AGZ  Stillwater, OK 
Systems Engineer
OSU Information Technology Department Telecommunications Services Group