K3 3051 audio buzz in chassis on SSB

[paulb]

Hi folks

K3 going perfectly fine here.
Just curious about an odd audio buzz
in the rear of the chassis under heavy
SSB modulation. It sounds like
transformer or frame slightly loose,
nothing appears loose or un-done.
Noticed when using the M1 audio
record - playback, so normally don't
hear it when using the mic.
Wonder if there is any particular area to
check ?

Antenna tuner is bypass;
Low vswr coax to antenna.


cheers

paul b

[Brett Howard]

Can you damp it by putting your hand on any of the chassis panels?

~Brett

On Sat, 2009-07-04 at 04:55 -0700, paulb wrote:

> Hi folks
>
> K3 going perfectly fine here.
> Just curious about an odd audio buzz
> in the rear of the chassis under heavy
> SSB modulation. It sounds like
> transformer or frame slightly loose,
> nothing appears loose or un-done.
> Noticed when using the M1 audio
> record - playback, so normally don't
> hear it when using the mic.
> Wonder if there is any particular area to
> check ?
>
> Antenna tuner is bypass;
> Low vswr coax to antenna.
>
>
> cheers
>
> paul b
>

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[Tom-N2YTF]

I have the same buzz, and no question it is not the case.  I find it particularly irritating when I have the built in voice keyer running and am in a quiet shack.  I can almost make out my voice from the sound....

My GUESS as I have not yet held it down while transmitting (my rig is at Elecraft for unrelated repair work), is that the heatsink for the internal amp is making the noise....at least the noise is coming from that area.  Although I have to agree that everything in my rig also seems very secure to the touch.

73,
Tom-N2YTF

Brett Howard wrote

Can you damp it by putting your hand on any of the chassis panels?

~Brett

On Sat, 2009-07-04 at 04:55 -0700, paulb wrote:
> Hi folks
>
> K3 going perfectly fine here.
> Just curious about an odd audio buzz
> in the rear of the chassis under heavy
> SSB modulation. It sounds like
> transformer or frame slightly loose,
> nothing appears loose or un-done.
> Noticed when using the M1 audio
> record - playback, so normally don't
> hear it when using the mic.
> Wonder if there is any particular area to
> check ?
>
> Antenna tuner is bypass;
> Low vswr coax to antenna.
>
>
> cheers
>
> paul b
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[e-mail]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[paulb]

Hi again folks

Follow up from original post;
I have run K3 on a dummy load on the bench.
Removed top cover, and transmit 100W SSB from the audio digi-memory M1.
The voice buzz is from the PA module, which I suppose is no big deal.
Removed the PA and checked all screws were tight, and put back into service.
No change to the audio buzz, it is my guess the PA final ferrite transformer magnetic
field is pretty strong, vibrating the core.

Interested to hear any follow up.

thanks

cheers from down under
Paul b
zl1ajy


I have the same buzz, and no question it is not the case.  I find it particularly irritating when I have the built in voice keyer running and am in a quiet shack.  I can almost make out my voice from the sound....

My GUESS as I have not yet held it down while transmitting (my rig is at Elecraft for unrelated repair work), is that the heatsink for the internal amp is making the noise....at least the noise is coming from that area.  Although I have to agree that everything in my rig also seems very secure to the touch.

73,
Tom-N2YTF


<quote author="Brett Howard">
Can you damp it by putting your hand on any of the chassis panels?

~Brett

On Sat, 2009-07-04 at 04:55 -0700, paulb wrote:
> Hi folks
>
> K3 going perfectly fine here.
> Just curious about an odd audio buzz
> in the rear of the chassis under heavy
> SSB modulation. It sounds like
> transformer or frame slightly loose,
> nothin