[Elecraft] K2 SSB audio distorted. Realignment, MIC gain mod etc.

[Don Wilhelm]

Andy,

I assume you have the K2/100 rather than the K2/10.  The KPA100 can 
couple into the KSB2 board giving audio distortion.  Remove the right 
side panel and tuck the ribbon cable and speaker cable up into the space 
between the KPA100 and the top of the Control Board.

Mods to increase the mic gain have been several - change the value of 
resistor R14 is the simplest, adding a mic preamp is a bit more 
involved, and for those who want a bit better performance there is the 
KI6WX SSB Increased RF Gain mod.  If the latter is installed in a 
K2/100, changes to the KSB2 ALC circuit should also be made - if you 
have a transistor added to your KSB2 near U5 (either on the top or 
bottom of the board), then you have that mod installed - I can give you 
the ALC changes that should be made.

Since you have an older KPA100, do you have the shield up to date?  You 
should have a shield on the speaker magnet, there should be clips on the 
shield and there should be a direct connection between the top of the 
shield and the SO-239 jack (that connection is usually made with 2 
solder lugs connected together).

73,
Don W3FPR


On 12/31/2011 2:47 AM, Andreas Hofmann wrote:
> Hi
>
> I have SN 2555 and have exclusively used it for CW. Now, I am trying to use it for SSB, but I am getting reports of distortion. Even with SSBA 1 and SSBC 1:1. If I speak really quietly, with microphone about 10 inches away, the distortion is manageable but not fully gone. ALC seems to go a couple of LEDS before it settles down to 1 LED on 40m. This happens for both MH2 and the Heil Pro-Set Plus!.  I believe, I did some mods years ago to increase MIC gain, but I have a hard time to find the information now on the website to double check.
>
> What would be the mostly likely reason my audio is distorted?
> I scanned the manuals but there is no procedure to align the MIC gain anywhere.  How can this be done?
> The rig is 7-8 years old, I am considering spending an evening and realigning everything.  Is this something that could fix this issue?
> If my memory is right, and there was a MIC gain mod at some point, can someone send me a copy/details, so I can investigate if I have it and possibly undo it?
>
> Thanks
> And 73, Andy, KU7T
>