[Elecraft] Sidetone Pin Pricks

Sun Apr 4 17:45:00 2004

Whilst I can't obviously speak for Wayne ! I was one of the people who 
helped come up with this mod and I have used it with complete satisfaction 
ever since .

I am fairly certain that what Wayne was referring to is that this mod slows 
down the action of the mute circuit (which is the desired effect) but 
slowing it down this much may create audible artifacts in some K2's, one 
possible fix for this side effect was to use j309 fets instead of j310s 
because they pinch off faster another alternative was to use wane's 
suggested mod (which I haven't tried ). It didn't cause any artifacts in my 
K2 and I am keeping the mod the way it is and can wholeheartedly recommend 
it as a complete cure for this noise.

the 'pin pricks' are caused by the /mute line cutting abruptly the received 
audio, in non dsp k2's it isn't a problem.
http://www.ac6rm.net/mailarchive/html/elecraft-list/2003-07/msg00477.html

At 02:56 04/04/2004, Kenneth A. Christiansen wrote:

>About a year ago I put the modification to get rid of the pin-pricks in
>my K2 sn 1031. I liked it but was discouraged from keeping it by Wayne's
>letter on this reflecter so I removed it. I end up turning down the AF
>gain while I transmitt. I would like to know what the problem is with
>using this modification and since it bothers many people on the list what
>is the proper way to solve this problem. I would like to put it back in
>my K2.
>
>Ken Christiansen W0CZ
>
>Message: 2
>From: "Indy" <[email protected]>
>To: <[email protected]>
>Date: Fri, 2 Apr 2004 06:39:45 -0700
>Subject: [Elecraft] sidetone pin-pricks
>
>I have "pin-pricks" in my sidetone when the QSK changes over.  this =
>began with the change from the KAF2 to the DSP.  Lyle has a mod he =
>suggests which slows the rate of the QSK way down.  Wayne suggests this:
>
> >"Another way to achieve the same effect is to insert a largish
> > resistor (try 100 k) in series with pin 17 on the MCU. This would add
> > only 150 microseconds to the /mute fall and rise times."
>
>Has anyone tried Wayne's suggestion?  I am not anxious to cut a trace =
>without knowing if it works!
>
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-- 
Brendan Minish
   [email protected]
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