[Elecraft] [K3] Shorting K3 PHONE jack outputs (WAS OT: Stereo to mono adapters)

[Don Wilhelm]

  James,

The only way to be certain is to examine the schematic of the adapter (I 
know, sometimes that is hard to come by), or to dope it out with your 
ohmmeter.  I have found some that do it either way.

The one you want is one that connects the ring and tip of the stereo 
plug to the tip if the mono jack.  That one will connect both the left 
and right channels together and do what you desire.

Sorry if the adapter nomenclature is confusing - in the midst of 
confusion and lack of information about how the various adapters are 
wired, it is usually easier to build your own adapter rather than 
relying on the "smarts" of someone else who assumes (but does not know) 
what you are trying to accomplish.

73,
Don W3FPR

On 12/3/2010 11:53 PM, James Sarte (K2QI) wrote:
> BTW, one thing I noticed is that both stereo to mono adapters I
> purchased short ring and tip together rather than ring to sleeve.
> Since both hot signals are combined, isn't there still a load being
> presented to the right channel amp?
>
> I know some adapters will short ring to sleeve, thereby presenting a 0
> ohm load to the amp.  In this case, that isn't happening.
>
> My ohm meter shows when using a stereo to mono adapter while connected
> to the mono DSP, ring and sleeve show a 22 ohm load; tip and sleeve
> show a 22 ohm load, and ring and tip have a 1 ohm load as they're
> shorted.
>
> Seems safe to me?
>
> Tnx,
> James K2QI
>
>
>
> On Fri, Dec 3, 2010 at 6:14 PM, Paul Christensen<w9ac at arrl.net>  wrote:
>> Jim (K9YC) is right.  When looking at the K3 schematic, realize that the
>> headphone amp's 8-ohm build-out resistors are not on the same schematic page
>> as the headphone amp.  At least it wasn't the last time I looked.
>>
>> Paul, W9AC
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