[Elecraft] K3(s) Headphone Splitter

[Josh]

You don't necessarily need transformers. If grounds from both radios bonded together it should be fine, depending on extent of "pin 1" problem internal to radio. 

Two SPDT toggle switches would accomplish this. One switch for each ear which selects between the two radios. That's assuming you only care about mono sources. 

If you need isolation transformers use 1:1 or close to that. I can suggest an inexpensive transformer from Mouser/Digi if needed. You'll also need a headphone amp.

I would certainly try the trivial solution first and if noisy, try to correct the grounding issue before throwing hardware at it. 

73
Josh W6XU

Sent from my mobile device

> On Apr 25, 2018, at 10:54 AM, Rich <rwnewbould at comcast.net> wrote:
> 
> I am planning to build a headphone splitter/switch so I can listen to one K3 in the left ear and the other radio in the right ear or turn off the audio from either radio.
> 
> Two questions:
> 
> Is there a commercial item for this purpose?
> 
> I know I will need an audio isolation transformer between each radio and the splitter/switch.   Any suggestions on what a good impedance value would be for those transformers?
> 
> Thanks
> 
> Rich
> 
> K3RWN
> 
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