Just measured that & 354 ohms tip to ground and the same for ring to
ground.
Seems like this is a problem for repair and they have a flat fee when
out of warranty... $100 & they send you a new pair in exchange. (or
$150 & the send you the QC3)
Seems as if this thread has been around long enough & some great
ideas have come through, thanks for the interest & I really
appreciate the interest.
73,
Gary
KA1J
> Check to see if the input impedance between the two channels is different.
>
> You may just have an 'open' signal ground on the effected channel. That
> could be a cold solder joint on the active circuit board or something as
> simple as a bad stereo jack connection. The human body effect would seem to
> indicate an open signal ground or at least a high resistance signal ground.
>
> Have Fun,
> Dave
> Wa3gin
>
> -----Original Message-----
> From: rfi-bounces@contesting.com [mailto:rfi-bounces@contesting.com] On
> Behalf Of Gary Smith
> Sent: Thursday, January 15, 2009 12:04 PM
> To: Rfi@contesting.com
> Subject: Re: [RFI] Hum in Bose QC2 headphones
>
> Tim,
>
> Anything is possible. I am going to my girlfriend's place this
> weekend and have an antenna there as well albiet only for 40 - 20M.
> But... if the problem is present I won't need to have the antenna
> connected. I'll have my laptop with me too so I can A>B that with
> them as well.
>
> I do not have this problem with my Sony, Sensheiser or el cheapo Koss
> headphones, only these powered noise cancelling ones.
>
> Tree mentioned something about perhaps my body having AC and my
> grounding myself reduces the AC & possibly testing for it by moving
> the headphones away to see if that stops the hum: The sounds from
> within the headset are too low for my hearing & I couldn't test that
> as once removed however little, I can barely hear anything from
> within the phones; but there's an interesting thought he brought up
> there as nothing I can connect or disconnect anywhere that kills the
> hum in that right side except when I touch something metal that is
> connected in any way to ground and that stops the hum 100%.
>
> Seems like in some integral way that being proximal to the headphones
> and them with the wiring attached is a functional part of the
> problem.
>
> Gary
> KA1J
>
>
> > 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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