I buy adapters all the time and I  never have a problem.


Sent from my iPhone

On Apr 5, 2010, at 1:13 PM, Martin McCormick  
<[log in to unmask]> wrote:

> 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