[Elecraft] K3 line out - Stereo vs Mono

[Joe Subich, W4TV]

Paul,

> Now that I have an answer to that I'll go with the recommended K3 RX
> <--> PC TX and K3 <--> TX to PC RX (solving the exchange of audio)

I would not bother connecting the RASCAL's receive side.  Simply use
the stereo audio cable between the K3 "Line Out" and the PC "Line IN".
Reserve the RASCAL for the FSK/PTT connection to the K3's AUX.

> Can I use the RCA PTT IN jack on the back of the rig to key it for
> RTTY, PSK, JT65, etc.? I prefer FSK to AFSK and hence would rather
> use PTT instead of VOX.

Sure you can.  However, if you already have the RASCAL and it provides
a PTT connection to the AUX jack, why not use it for PTT even with
PSK/JT65A/etc.?  I assume the RASCAL is an FSK interface with RX audio
from Line Out and FSK/PTT to AUX (DB15HD).

If, on the other hand, RASCAL is a simple passive audio box with a
serial control port, connect the PTT line from it to the RCA PTT jack
and use two stereo audio cables from the K3 to the computer sound card
(you don't want to cascade transformers - it's unnecessary and prone
to distortion given the quality of the transformers in some external
boxes).

73,

    ... Joe, W4TV


On 12/6/2012 9:42 PM, Paul M Dunphy wrote:
> On 12/6/2012 9:29 PM, Don Wilhelm wrote:
>> Paul,
>>
>> I believe you may be trying to address too many issues at once. Take
>> then one at a time.
>> As far as the speaker goes, I suggest the safest solution is to
>> re-wire the plug to a stereo plug using only the tip and the shell.
>>
>> Look st the plug - if the plug does not have a ring on it, then it is
>> not a stereo plug.
>>
>> The  speakers question does not have any direct relationship with the
>> MMTTY input.
>>
>> 73,
>> Don W3FPR
>
>   Hi Don,
>
>       I provided too much info.  I do not want to ever use an external
> speaker.  I use stereo headphones 99% of the time, and for the few times
> I don't, I'll use the K3's stock speakers . . .
>
>      My concern was the warning in the manual errata saying that if one
> did use an external speaker with a mono plug, you could damage the right
> channel amplifier (unless you made the suggested menu changes.)  The
> Line Out is labelled stereo, and like the eternal speaker one, it has
> the same triangle icon with an exclamation mark beside it.  I was
> concerned that plugging a mono plug into it would risk the same
> potential danger as plugging a mono plug into the external speak jack.
> In a subsequent post, Joe W4TV, says the warnings do not apply to the
> Line Out because it contains current limiting resistors.  That was the
> main reason for my question.  I gave too much background and and lead in
> . . . I should have simply said:
>
> Is it OK to use a mono plug in the stereo Line Out K3's jack? <G>
>
>      Now that I have an answer to that I'll go with the recommended K3
> RX <--> PC TX and K3 <--> TX to PC RX (solving the exchange of audio)
>
>      Next (and hopefully last question):
>
>      Can I use the RCA PTT IN jack on the back of the rig to key it for
> RTTY, PSK, JT65, etc.?  I prefer FSK to AFSK and hence would rather use
> PTT instead of VOX.
>
> 73, Paul VE1DX
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