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KX3 high pitched hum on headphone jack

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kg4olw

KX3 high pitched hum on headphone jack

When I plug headphones into the headphone jack, there is a very sharp loud high pitched hum just at the edge of my hearing, the noise is independent of volume level, and is on all modes except fm. The noise gives me a headache in a few seconds, and is loud enough that I am concerned about my hearing. Additionally when I have headphones on and I am in SSB mode, I can hear the pulses as the vfo turns.

Any thoughts on what it could be?

kg4olw

Re: KX3 high pitched hum on headphone jack

Ok, playing with the radio I noticed if I enable RX IQ the noise goes away. The noise is only present with RX IQ disabled. Can anyone else verify this?

kg4olw

Re: KX3 high pitched hum on headphone jack

Just as an update I am trying to tune in a very weak signal am radio station. Another thing i noticed today while messing around is that besides noise from the pc, I also experienced additional noise when it is plugged into my bargain bin pyramid 25amp switching power supply. I never noticed this on HF, so maybe it is just more pronounced on AM. Any suggestions on a good linear power supply that will also support the draw of the kxpa100?

Stephen Selberg

Re: KX3 high pitched hum on headphone jack

I had that same garbage power supply. Got rid of it and stuck it in the
garage to collect dust. It was causing all kind of noise in the shack. I
bought the alinco switching supply and have been very happy with it. I use
it primarily to power my TS-590. I like it because you can vary the voltage
between 5-15v. It's the DM-330. Very easy to pack up and take on the road
with me.

73,

Steve KS6PD

KX3 #3604

On Wednesday, June 26, 2013, kg4olw wrote:

> Just as an update I am trying to tune in a very weak signal am radio
> station.
> Another thing i noticed today while messing around is that besides noise
> from the pc, I also experienced additional noise when it is plugged into my
> bargain bin pyramid 25amp switching power supply. I never noticed this on
> HF, so maybe it is just more pronounced on AM. Any suggestions on a good
> linear power supply that will also support the draw of the kxpa100?
>
>
>
> --
> View this message in context:
> http://elecraft.365791.n2.nabble.com/KX3-high-pitched-hum-on-headphone-jack-tp7575558p7575878.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
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Don Wilhelm-4

Re: KX3 high pitched hum on headphone jack

In reply to this post by kg4olw

The Astron 6 amp linear supply comes to mind. There are some good
switchers out there, see the ARRL Product reviews for an independent
assessment.

73,
Don W3FPR

On 6/26/2013 6:24 PM, kg4olw wrote:

> Just as an update I am trying to tune in a very weak signal am radio station.
> Another thing i noticed today while messing around is that besides noise
> from the pc, I also experienced additional noise when it is plugged into my
> bargain bin pyramid 25amp switching power supply. I never noticed this on
> HF, so maybe it is just more pronounced on AM. Any suggestions on a good
> linear power supply that will also support the draw of the kxpa100?
>
>
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/KX3-high-pitched-hum-on-headphone-jack-tp7575558p7575878.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

Jim Wiley

Re: KX3 high pitched hum on headphone jack

The 6 amp Astron would not do the job. He needs a supply capable of
more like 20 to 25 amperes to handle the load presented by the rig plus
the amplifier. The Astron 20 or 35 ampere models should do the job,
with the 35 amp version having some extra reserve so he could run the
rigs he describes plus something else, such as a separate VHF/UHF FM
transceiver.

My K2 plus the combination KPA100 / KAT100 in an EC2 draws 17 to 20
amperes at 100 watts output, depending on band and the actual voltage of
the "12 volt" source.

As you state, there are are some good 25 amp switchers out there, such
as the MFJ 4125 and the Astron SS-25 that have been tested for low RF
noise.

- Jim, KL7CC

On 6/26/2013 7:36 PM, Don Wilhelm wrote:

> The Astron 6 amp linear supply comes to mind. There are some good
> switchers out there, see the ARRL Product reviews for an independent
> assessment.
>
> 73,
> Don W3FPR
>
> On 6/26/2013 6:24 PM, kg4olw wrote:
>> Just as an update I am trying to tune in a very weak signal am radio
>> station.
>> Another thing i noticed today while messing around is that besides noise
>> from the pc, I also experienced additional noise when it is plugged
>> into my
>> bargain bin pyramid 25amp switching power supply. I never noticed
>> this on
>> HF, so maybe it is just more pronounced on AM. Any suggestions on a good
>> linear power supply that will also support the draw of the kxpa100?
>>
>>
>>
>> --
>> View this message in context:
>> http://elecraft.365791.n2.nabble.com/KX3-high-pitched-hum-on-headphone-jack-tp7575558p7575878.html
>> Sent from the Elecraft mailing list archive at Nabble.com.
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

Don Wilhelm-4

Re: KX3 high pitched hum on headphone jack

Ooops, I overlooked the amp. Jim's recommendations are very good.

73,
Don W3FPR

On 6/27/2013 1:59 AM, Jim Wiley wrote:

> The 6 amp Astron would not do the job. He needs a supply capable of
> more like 20 to 25 amperes to handle the load presented by the rig
> plus the amplifier. The Astron 20 or 35 ampere models should do the
> job, with the 35 amp version having some extra reserve so he could run
> the rigs he describes plus something else, such as a separate VHF/UHF
> FM transceiver.
>
> My K2 plus the combination KPA100 / KAT100 in an EC2 draws 17 to 20
> amperes at 100 watts output, depending on band and the actual voltage
> of the "12 volt" source.
>
> As you state, there are are some good 25 amp switchers out there, such
> as the MFJ 4125 and the Astron SS-25 that have been tested for low RF
> noise.
>
> - Jim, KL7CC
>
>
> On 6/26/2013 7:36 PM, Don Wilhelm wrote:
>> The Astron 6 amp linear supply comes to mind. There are some good
>> switchers out there, see the ARRL Product reviews for an independent
>> assessment.
>>
>> 73,
>> Don W3FPR
>>
>> On 6/26/2013 6:24 PM, kg4olw wrote:
>>> Just as an update I am trying to tune in a very weak signal am radio
>>> station.
>>> Another thing i noticed today while messing around is that besides
>>> noise
>>> from the pc, I also experienced additional noise when it is plugged
>>> into my
>>> bargain bin pyramid 25amp switching power supply. I never noticed
>>> this on
>>> HF, so maybe it is just more pronounced on AM. Any suggestions on a
>>> good
>>> linear power supply that will also support the draw of the kxpa100?
>>>
>>>
>>>
>>> --
>>> View this message in context:
>>> http://elecraft.365791.n2.nabble.com/KX3-high-pitched-hum-on-headphone-jack-tp7575558p7575878.html
>>> Sent from the Elecraft mailing list archive at Nabble.com.
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:[hidden email]
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
>
>