Jim,
Definitely a hum as opposed to a buzz.
As I sit this moment with them on, the hum is on the right. Turning
off the AStron Linear supply to the K3 & bench does nothing to
attenuate the hum. Turning off the Titan 425 did nothing. Now there
is nothing on except the computer and when I am done with this letter
I will send it and turn off the computer.
Thing is it's not an issue with my Sony MDR-7506 headphones or my el
cheapo Koss headsets but they are not powered headsets & the QC2 runs
off a single AAA battery.
Now my iambic paddles are 1' away and feed directly to the K3. Each
of the three terminals on it are exposed with knurled knobs but the
middle knob is connected to ground. I can touch either of the knobs
and the hum stops 100%. I play stringed instruments so I have
calouses on my left hand. If I touch either of the knobs with the tip
of my finger or my finger nail, there is absolutely no audible
change. But touch with the moist part of my finger and the resolution
is 100%.
I can almost get used to the hum but when it goes away I see how much
it really interferes...
Gary
KA1j
> On Tue, 13 Jan 2009 23:09:00 -0500, Gary Smith wrote:
>
> >Though not a RFI issue, perhaps someone has the solution?
>
> If what you hear is HUM (pure 60 Hz) rather than BUZZ (little or no
> 60 Hz, but lots of 180, 360, 420, etc.) suspect a magnetic field
> coupling problem. If what you hear is BUZZ, suspect power-related
> noise present between your equipment. Solutions (and detailed
> explanations) are here:
>
> http://audiosystemsgroup.com/RFI-Ham.pdf
>
> http://audiosystemsgroup.com/HamInterfacing.pdf
>
> 73,
>
> Jim K9YC
>
>
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>
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