[Elecraft] Sidetone with harmonics at 400 Hz...

[Ken K3IU]

Hi Steve:
Sometime between s/ns 2888 and 3442 that I built, there was a mod to the 
sidetone circuit that added on the control board an inductor (now L1 
82mH) and a resistor (R11 47K) to "round off" the square wave. I do not 
know if that was included in the major mod to bring up pre 3000s to the 
latest mods. I think it is called the K2ATOBKT.  I do NOT recall any 
complaints specifically like the 2nd harmonic problem when set at 400 Hz.
73,
Ken Wagner K3IU

Steve Kallal wrote:
> I have a K2, serial #2289, that has a second harmonic in the sidetone. The
> sidetone is set for 400 Hz because I do much better with lower pitches. The
> sidetone at 400 Hz has a definite square wave sound to it. The problem
> certainly is not present at 600 Hz, and I don't even want to try 500 Hz. I'd
> go lower than 400 Hz if the K2 allowed it.
>
> I talked to Don Wilhelm about this and he seemed puzzled. There is a post
> off of the Elecraft web site about this at
> http://www.qsl.net/ve3mcf/elecraft_reflect/K2_Sinewave_Sidetone.txt. But
> that thread is dated Winter 2000. I would think the K2 has gone through
> enough evolutions to correct this. Perhaps not?
>
> Has anyone had this problem and corrected it? The sidetone is useable but
> annoying. It also makes zero beating a signal a lot harder.
>
> 73,
>
> Steve N6VL
>
> _______________________________________________
> Elecraft mailing list
> Post to: Elecraft at mailman.qth.net
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft    
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>
>