[Elecraft] K3 AM reception

[Wes Stewart]

Hi Bill,

Supposedly my S/N has the mods already. Nevertheless, I don't use the line output for anything normally and speakers are for listening to music.  I won't be wasting my time looking for the problem if I wasn't actually hearing it too in my good quality headphones.

Regards,

Wes


--- On Mon, 2/2/09, Bill W4ZV <btippett at alum.mit.edu> wrote:

> From: Bill W4ZV <btippett at alum.mit.edu>
> Subject: Re: [Elecraft] K3 AM reception
> To: elecraft at mailman.qth.net
> Date: Monday, February 2, 2009, 10:01 AM
> Wes Stewart wrote:
> > 
> > Following are links to plots that demonstrate some of
> the "fun" I'm
> > having.  The first two are taken using Spectrum Lab to
> look at the Line
> > Out audio signal from the K3.  The input signal is
> from a homebrew 28.7
> > MHz crystal oscillator/buffer with about a -70 dBm
> output level.  For
> > these particular plots the K3 mode was set to LSB,
> although I saw, but
> > didn’t record the same issue on CW.  The beat note
> is 450 Hz. The Line Out
> > is run into the microphone input of the built-in sound
> card in my Lenovo
> > T400 laptop.  Care was taken to insure that the sound
> card wasn't being
> > overdriven.
> > 
> 
> Have you done the AF Stage Upgrade?  
> 
> "While the K3's speaker and line outputs meet the
> original K3 distortion
> specifications at their intended levels of operation,
> we've found that
> further improvement is possible, especially at higher
> volume levels, with
> minor component changes. Low level distortion products can
> be further
> reduced at both outputs. These changes are being
> incorporated into new K3s."
> 
> http://www.elecraft.com/K3/mods/K3_AF_Stage_Upgrade_Instructions_Rev_B.pdf
> 
> Do you notice the same distortion when using the headphone
> output?  I have
> good ears and a lot of experience on CW.  All 3 of the K3s
> I've had have
> excellent audio fidelity when using a good set of
> headphones (headphone
> output has apparently never had this problem).  This also
> sounds very
> similar to UR5LAM's issue posted about some 3 months
> ago, which I believe
> resulted in the above mod.
> 
> 73,  Bill
> 
> -- 
> View this message in context:
> http://n2.nabble.com/K3-AM-reception-tp2254009p2259061.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> 
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