[Elecraft] KPA 500 Hum PC Speakers.

[Bill K9YEQ]

Note the changed subject.  Computer speakers are cheaply made, no shielding.
If you are lucky won't have issues.  In your cases, suggest moving them away
from equipment.  Don't forget that stray rf loves audio as well.  Grounding,
antenna location, etc. can all play a role.   (I have no hum while
transmitting.  I did add an isolator between the K3 and amplified PC
Speakers.)
 
73,
Bill
K9YEQ


-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of n5ge at n5ge.com
Sent: Monday, August 01, 2011 2:14 PM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] KPA 500 Hum


Klaus,

Are you sure it is the KPA500?

My computer speakers in the shack will hum when using any of my HF
amplifiers on CW.

73,
Tom
Amateur Radio Operator N5GE
ARRL Lifetime Member
QCWA Lifetime Member


On Mon, 1 Aug 2011 07:33:05 +0000, Klaus Koppendorfer <KK at ccf.net> wrote:

>
>Last week i assembled the kpa500 of oe6rdd when we transmit we hear a 
>realy loud hum (50hz) in the rythm of the cw signals
>
>i have compared this with my own kpa-500 and there is no hum i have 
>tried to loosen the big srew which holds the tranformer with no result
>
>any ideas ??
>