[Elecraft] K3 - Splitting main/sub audio to 2 headphones

[Joe Subich, W4TV]

On 2014-06-01 1:02 AM, Don Wilhelm wrote:>
 >
> You should have no problems with paralleling 2 headphones on the
> audio output of the K3, with no need for any external mixer.

I would not risk it.  The K3 headphone amplifier is only rated for
105 mW at 16 Ohms.  Both power dissipation (heat) and distortion
rise significantly as the load impedance drops and the output power
increase.

I would recommend use of a headphone amp - even without individual
balance capabilities - and individual adapter cables for each user.
Connect tip on the amplifier to both tip and sleeve on the headphones
for the operator using the main RX and connect ring to tip and ring
for the operator using the sub RX.

Since the outputs of the headphone amplifier/splitters are generally
isolated, one could even make cables with a 1K or 5K pot to create
their own "balance/mix" control.

73,

    ... Joe, W4TV


On 2014-06-01 1:02 AM, Don Wilhelm wrote:
> Stew,
>
> You should have no problems with paralleling 2 headphones on the audio
> output of the K3, with no need for any external mixer.  If there is a
> significant difference in the response (SPL) of the two headphones, that
> may present a volume problem, in which case, some secondary
> amplification may be required for one or the other set of headphones.
> Since the gaming headset has a volume control, that alone may be
> sufficient - try it and see what the result may be.
>
> 73,
> Don W3FPR
>
> On 5/31/2014 5:20 AM, Stewart Rolfe wrote:
>> I want to have a second op listening to the sub rx on a separate pair
>> of phones (for 6m trophy, so same band). I've strung together 2 stereo
>> sockets with one fed from the right and the other from the left side
>> of the front panel phone output and this seems to works well. With the
>> channels linked I get Main in both ears in one headphone set and Sub
>> in both ears in the other, and when the sub rx is off there is Main in
>> both.
>>
>> I'll be using a Yamaha CM-500 and a gaming headset so I'm wondering if
>> I should be loading the audio with 2 headphones without any buffering
>> etc. A cheap mixer with separate amps would be good and may give
>> better volume control although the gamers have an inline volume
>> control on the lead. A quick search however hasn't found a mixer that
>> separates the input channels.....
>>
>>
>
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