[Elecraft] Comment on 2nd filter mod

Sun Jan 12 17:08:01 2003

Thanks Ron and John,   I was using the headphone jack and the filter does
look flatter using the external speaker jack.  I appreciate the help.  I had
no idea that using the headphone jack could affect things.  I checked SSB
receive on WWV and the sidebands do sound the same.  Guess that's all I can
ask for.  Thanks again, Todd

----- Original Message -----
From: "Ron D'Eau Claire" <[email protected]>
To: "'Elecraft Mailing List'" <[email protected]>
Sent: Sunday, January 12, 2003 1:33 PM
Subject: RE: [Elecraft] Comment on 2nd filter mod

> I'll add to John's comments to make SURE that you are picking up the
> audio from the Aux Speaker jack, NOT the "phones" jack. The caps in the
> phones output circuit in the K2 roll of the response quite a bit, giving
> the Spectrogram display a "tilt" that really isn't in the filters.
>
> Of course, if you took all your measurements through the phone's jack,
> you should see an improvement, but it won't be as flat as a lot of the
> images you will see of the "improved" filter.
>
> The biggest thing I noticed after installing the mod was in how the two
> sidebands SOUNDED, without even looking at Spectrogram. The "2nd Xfil
> Flattening" mod came about right after I got my K2 assembled and noticed
> that the two sidebands sounded totally different. Just listening to the
> background noise told me that one had a LOT of high emphasis that the
> other sideband lacked. To me, it made listening to SSB on the upper
> bands irritating.
>
> Then the mod appeared on the reflector here and I installed it
> immediately.  I could still hear a slight difference in the sound of the
> background noise when switching from USB to LSB (that was before the
> more carefully matched filter crystals were available) but the audio of
> a SSB signal sounded the same to my ear on either sideband.
>
> Ron AC7AC
> K2 # 1289
>
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