[Elecraft] Fixed level audio output for K2

[Julian (G4ILO)]

Thanks for the suggestion. The one I've implemented was sent to me off-list 
by Joe Levy. I've taken the output via a capacitor from the junction of R10 
and Q1, 2 and 3 on the KAF2 board. There is more than ample output to drive 
the line input of the sound card, without any additional amplification at 
all. I have not noticed any hum, either.

73,
--
Julian, G4ILO. (RSGB, ARRL, G-QRP, K2 #392)
G4ILO's Shack: http://www.qsl.net/g4ilo



  ==== Original message ====

> I have just completed a 10x amplifier (using one half of an LM358) that
> I intend to put between the top of the audio pot and the output. The
> original direct output suffers from too low level to drive a PC
> soundcard sometimes, and also if the shielding/grounding is not good
> enough, it will pass hum back into the K2. 
> 
> The amplifier is completed and tested, but not yet installed in the K2.
> It is tiny and can be glued to the back of the front panel board. Why is
> it so tiny? Well, it was made mostly with surface mount components. 
> 
> It is possible to use the other half of the LM358 as a mixer with one
> input for the sidetone, one for the microphone and one for the normal
> audio. I won't do that intially, as it means routing wires from board to
> board, but I may put the sidetone in there eventually.
> 
> Sverre
> LA3ZA
>