I wonder if there is a problem with your AC house/shack wiring? Missing
ground at the breaker panel or a connection between the ground wire and
neutral missing or miss wired?
It might be worth trying your K3 setup (or even the other related hum
devices) at another Ham's house to see if the hum in the QC-2 is there.
73,
Tim K3LR
-----Original Message-----
From: rfi-bounces@contesting.com [mailto:rfi-bounces@contesting.com] On
Behalf Of Gary Smith
Sent: Thursday, January 15, 2009 9:00 AM
To: Rfi@contesting.com
Subject: Re: [RFI] Hum in Bose QC2 headphones
Ron,
I hadn't thought to do that but it is worth while & I'll check that
out. It would have to be a wall wart in that everything else here is
three prong.
Interesting that while running my laptop plugged in to its PS I have
the same problem. I just disconnected the laptop and the hum goes
away.
Same with my Sansa MP3 player, it works perfectly with these QC2
headphones. However I just now connected the Sansa to the USB charger
and with that the hum is back.
The connector in the headphone is a custom one designed to mould
seamlessly with it's ajacent insertion surface; I'll have to see if
Radio Shack has a straight stereo cable that will fit in there, It's
seeming more & more like it's either a design defect or the wire is
in some way defective. There is a switch on the headphone end of the
plug which changes the Z to match the input source and changing the
setting does nothing. Maybe the issue is in that mechanism...
The real issue for me is the quality of reception with these noise
cancelling headsets is the best I have ever heard, It's like
listening through the worlds best headphones in relative silence.
They're to this point perfect for copy and far better than other
headsets I have including a nice studio set that is arguably more
accurate in reproduction quality but do not cancel the outside noise
anywhere close to these. Given the two options, the QC2 is miles
ahead except for that %^&*()@ hum.
Last night I gave in & ran a connector from the computer chassis to
my ankle and that killed the buzz 100% & worked the TS7C on 160M He
was faint here but with the quality of the K3's diversity receive &
those headsets, he was perfect Q5 as in a true 519.
Gary
KA1J
> Is it worth checking to see of there are any two prong plugs on the 120V
> circuit and plugging them in 180 the other way (including wall warts)??
>
> 73 es God Bless de KK1L...Ron Rossi (kk1l@arrl.net) <><
> QTH: Jericho, Vermont
> My page: http://home.comcast.net/~kk1l
>
> WX5L wrote:
> > Gary,
> >
> > At this point you need to check that the ground(s) in the headphone jack
are still secure to the chassis of the rig. It seems that the result of a
poor ground from the jack to the chassis could be the culprit. Open the rig
and inspect the grounds. There may be seperate ground paths for tip and
ring(stereo). The ground for one side may have been interrupted.
> >
> > Randy
> > WX5L
> > --
> >
> >
> > WX5L
> > Thibodaux, LA
> >
> > ---- Gary Smith <wa6fgi@sbcglobal.net> wrote:
> >> >From the other Gary Smith.
> >> Are those Bose headphones *really* worth that kind of money? Have seen
their ads, just curious if they are that much better in service on a HF rig
than other brands.
> >> 73,
> >> Gary...wa6fgi
> >>
> >> ----- Original Message -----
> >> From: Gary Smith
> >> To: Rfi@contesting.com
> >> Sent: Wednesday, January 14, 2009 6:32 AM
> >> Subject: Re: [RFI] Hum in Bose QC2 headphones
> >>
> >>
> >> > Are you certain that both ends of the cable are plugged
> >> > in securely? I've heard the symptoms you described when
> >> > the plug on the headphone wasn't fully seated. Please
> >> > let us know what you find.
> >> >
> >> > 73
> >> >
> >> > -Kirk K4RO
> >>
> >> Hi Kirk,
> >>
> >> Indeed they are all the way in on both ends & that pesky hum remains.
> >> While assuring they are seated well I tried something, which was to
> >> have the headphones on and the stereo plug unplugged at the distal
> >> end.
> >>
> >> When not connected there was no hum but when I touched the bare end
> >> of the plug to the equipment ground the right sided hum showed up.
> >> Nothing surprising here but the same hum showed up regardless of
> >> which terminal was touched to ground be it tip, ring or ground.
> >>
> >> Interestingly if I touch the bare connector with my fingers, there is
> >> no hum whatsoever.
> >>
> >> The plot sickens
> >>
> >> Gary
> >> KA1J
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