[Elecraft] [EXTERNAL] Re: K2 audio problem

[Pawlak, Daniel L]

Don,
   Thanks for the advice. I did the alignment with Spectrogram. A few of the filters were off, and I corrected them. However, it didn't make much difference in improving SSB intelligibility. I then realized that the KDSP2 might be introducing artifacts to the audio.  I turned the denoiser off, and the audio was much better, but the noise was unbearable. I was gong to play with the various settings, when I remembered there were many differing opinions on how to set them up properly, and I think the conclusion was that the factory settings should be used. Did I recall correctly? If that's the case, can you share them with me? I might have mucked them up a long time ago.
73,
Dan  KF4KKF
________________________________________
From: Don Wilhelm [donwilh at embarqmail.com]
Sent: Sunday, July 22, 2018 2:04 PM
To: Pawlak, Daniel L; elecraft at mailman.qth.net
Subject: [EXTERNAL] Re: [Elecraft] K2 audio problem

Dan,

Align the IF filters.  I have no idea what may have made them change,
unless you tried to do a Master Reset which would change the filter
settings back to factory defaults, which only work well in a few K2s.

It is best if you use an audio spectrum analyzer running on your
computer to see where the filter passband is located in the audio spectrum.

Information on how to set up Spectrogram can be found on Tom Hammond's
(N0SS, now SK) website which has been preserved at
https://urldefense.proofpoint.com/v2/url?u=http-3A__www.mmccs.com_mmarc_n0ss_k2-5Ffilters-5Fusing-5Fgram-5Fv5r17.pdf&d=DwICaQ&c=YC-d702opsuYKpiO2Bmlzg&r=kP1njbluGgLcMdyEofM_F-lOGeRxHPEzfZ061VLXuAc&m=Sf-V4Vad14JSlM60ZznWp6L217ZRrXQqyxHStbeBmgY&s=3poR3hBdK3n1-SXX_YitFbw26l5srWNxRxpeNqfoCwE&e=.

If you need a copy of Spectrogram, go to my website https://urldefense.proofpoint.com/v2/url?u=http-3A__www.w3fpr.com&d=DwICaQ&c=YC-d702opsuYKpiO2Bmlzg&r=kP1njbluGgLcMdyEofM_F-lOGeRxHPEzfZ061VLXuAc&m=Sf-V4Vad14JSlM60ZznWp6L217ZRrXQqyxHStbeBmgY&s=lXG8j1NvNQy33wPnljdeJS8T7K4Aape696X1oRpqDfY&e= and
scroll near the bottom of the opening page.  There you will find links
to Spectrogram version 5.17 and version 16.  These files are local to my
website.

If you did a Master Reset, also refer to the K2 dial Calibration article
on my website.  You will have to do a CAL PLL in addition to the filter
alignment (CAL FIL).

Advice to all - do not do a K2 Master Reset unless you first record ALL
your menu settings, including the Filter settings.  The first few pages
of the K2 A to B upgrade instructions has instructions for recording all
you menu settings.  Restore them after a Master Reset.

73,
Don W3FPR

On 7/22/2018 1:36 PM, Pawlak, Daniel L wrote:
> I'm having trouble figuring out what's wrong with my K2 (serial 3957). It's been a very long time since I turned it on and now the audio sounds horrible. It sounds like it's muffled or like I'm listening to the speaker at the end of a long tube. High frequencies seem to be diminished. I've started doing an alignment, but have not found anything wrong so far. Any ideas on how to fix this problem?
> Thanks.