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Using a PC headset with K3, connections reverse at rear MIC jack?

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G3XAQ

Using a PC headset with K3, connections reverse at rear MIC jack?

Hi All,

I'm a new K3 owner so please be gentle.

I'm not a great SSB user so I want to use my cheap PC gaming/Skype
headset on the odd occasions I use sideband. It has separate 3.5mm plugs
for headphones and microphone so the K3's rear panel jacks seem the
obvious place for connection.

The Headset is a Plantronics 380. Although undocumented, I'd be
astonished if the mic is anything other than an electret condenser element.

The headset works fine on my IBM T60 laptop but doesn't work with the
K3. And yes, I have switched on the bias.

Poking about with a voltmeter and an unused stereo jack plug I find that
the bias on my laptop is +5V ring to sleeve. On the K3 it is +7.5V tip
to sleeve. I assume the audio is on the tip on the laptop and the ring
on the K3. I've not seen any other comments about this on the reflector,
but perhaps I have not looked carefully enough.

Why would Elecraft do it this way, so these gaming headsets don't work
without an ugly crossover adapter? Is there any non-soldering way to
change the connections on the rear panel Mic jack?

Thanks,

Alan G3XAQ
--

Alan Ibbetson
[hidden email]
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Nr4c

Re: Using a PC headset with K3, connections reverse at rear MIC jack?

Just don't worry about it. It'll work just fine. Follow direction in manual to set levels and be sure 'rPL bias' is selected for mic. I have used the Yamaha CM500 as well as a common Creative Labs 'desk' mic with my K3. All work well.

...bill nr4c

Sent from my Verizon Wireless 4G LTE DROID

Alan Ibbetson <[hidden email]> wrote:

>Hi All,
>
>I'm a new K3 owner so please be gentle.
>
>I'm not a great SSB user so I want to use my cheap PC gaming/Skype
>headset on the odd occasions I use sideband. It has separate 3.5mm plugs
>for headphones and microphone so the K3's rear panel jacks seem the
>obvious place for connection.
>
>The Headset is a Plantronics 380. Although undocumented, I'd be
>astonished if the mic is anything other than an electret condenser element.
>
>The headset works fine on my IBM T60 laptop but doesn't work with the
>K3. And yes, I have switched on the bias.
>
>Poking about with a voltmeter and an unused stereo jack plug I find that
>the bias on my laptop is +5V ring to sleeve. On the K3 it is +7.5V tip
>to sleeve. I assume the audio is on the tip on the laptop and the ring
>on the K3. I've not seen any other comments about this on the reflector,
>but perhaps I have not looked carefully enough.
>
>Why would Elecraft do it this way, so these gaming headsets don't work
>without an ugly crossover adapter? Is there any non-soldering way to
>change the connections on the rear panel Mic jack?
>
>Thanks,
>
>Alan G3XAQ
>--
>
>Alan Ibbetson
>[hidden email]
>______________________________________________________________
>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
>

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Don Wilhelm-4

Re: Using a PC headset with K3, connections reverse at rear MIC jack?

In reply to this post by G3XAQ

Alan,

In most cases, the tip and ring of computer microphones are connected
together. I don't know the particulars of your headset, but yours may
be different.

Yes, the K3 applies bias to the tip contact. It works with most
microphones that way.
You may have to modify the plug on that headset if the tip and ring are
not connected together (or build an adapter - it will be hidden behind
the K3, so 'ugly' should not be a problem).
It should still work on the computer with the tip and ring connected
together.
The alternative is to buy a Yamaha CM500 or the Elecraft ProSet K2.

73,
Don W3FPR
On 10/29/2013 10:32 AM, Alan Ibbetson wrote:

MontyS

Re: Using a PC headset with K3, connections reverse at rear MIC jack?

In reply to this post by G3XAQ

Alan,

The rear mic jack is a mono, not stereo, jack. It will short the ring and
sleeve together. Audio is on the tip, as is the voltage. The mic should
have a blocking capacitor to isolate the audio from the voltage.

This is standard for every radio I have owned. If a stereo jack is used, it
would be for PTT, not a separate bias connection.

Monty K2DLJ

Why would Elecraft do it this way, so these gaming headsets don't work
without an ugly crossover adapter? Is there any non-soldering way to
change the connections on the rear panel Mic jack?

Thanks,

Alan G3XAQ
--

Alan Ibbetson
[hidden email]

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Iain MacDonnell - N6ML-2

Re: Using a PC headset with K3, connections reverse at rear MIC jack?

On Tue, Oct 29, 2013 at 8:22 AM, MontyS <[hidden email]> wrote:
> The rear mic jack is a mono, not stereo, jack. It will short the ring and
> sleeve together.

Pretty sure that's not true. I believe that the connector is a TRS
type, but the ring is not connected to anything. The schematic for the
KIO3 Audio IO Board shows this too.

73,

~iain / N6ML
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Jim Brown-10

Re: Using a PC headset with K3, connections reverse at rear MIC jack?

In reply to this post by MontyS

On 10/29/2013 8:22 AM, MontyS wrote:
> The rear mic jack is a mono, not stereo, jack. It will short the ring
> and sleeve together.

As Iain has noted, this is incorrect. It's a TRS jack that uses only the
tip and sleeve contacts.

> Audio is on the tip, as is the voltage.

Right.

> The mic should have a blocking capacitor to isolate the audio from the
> voltage.

Nope. The mic includes a FET line drive that NEEDS the DC voltage to
operate (the bias). In general, the value of voltage is non-critical,
5-8 VDC is in the range, and the voltage is applied through a series
resistance in the range of 5-8 k Ohms. That's what's inside the K3, and
you can use your PC mic with other rigs by making a suitable adapter for
them wired in this manner.

Every ham rig I've seen manufactured in the past 30-40 years provides
bias voltage in that range on one pin of the mic jack, and the input is
DC blocked by a suitable capacitor.

73, Jim K9YC
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G3XAQ

Re: Using a PC headset with K3, connections reverse at rear MIC jack?

In reply to this post by G3XAQ

Hello again. Thanks to so many people for their detailed help and
suggestions. I seem to have solved the problem.

First: yes, Don is correct, this Plantronics headset microphone has tip
and ring connected together, just like every other PC headset on the
planet. That means my laptop offering bias on ring and Lyle offering
bias+audio on tip makes no difference.

No I can't follow the herd and buy a CM500, because nobody stocks them
in the UK and shipping from the US together with UK taxes makes the cost
unreasonable.

This headset mic shows 6.8K to ground. I tried a different PC headset
which shows 1K to ground and that one works perfectly with the K3 (and
my PC of course). I'd also noticed that the Plantronics worked for a few
seconds whenever I switched between rP.H bIAS and rP.H - ie when I
toggled the bias in either direction, on or off.

So, on the grounds of "well, maybe I need to suck some current outa the
K3 to keep a cap charged/discharged or bias the input correctly" I added
a 1K2 across the Plantronics mic. Hey presto: we have voice.

Maybe someone who carries the KIO3 circuit in their head can educate us
as to why the resistor bodge works, and perhaps put a range of values on
it for the benefit of others who may tread this path with yet another
flavour of not-Yamaha headset.

And now on to fiddling with TX EQ and suchlike. "Can you hear me,
Mother?"....

73, Alan

On 29/10/2013 14:32, Alan Ibbetson wrote:

> Hi All,
>
> I'm a new K3 owner so please be gentle.
>
> I'm not a great SSB user so I want to use my cheap PC gaming/Skype
> headset on the odd occasions I use sideband. It has separate 3.5mm plugs
> for headphones and microphone so the K3's rear panel jacks seem the
> obvious place for connection.
>
> The Headset is a Plantronics 380. Although undocumented, I'd be
> astonished if the mic is anything other than an electret condenser element.
>
> The headset works fine on my IBM T60 laptop but doesn't work with the
> K3. And yes, I have switched on the bias.
>
> Poking about with a voltmeter and an unused stereo jack plug I find that
> the bias on my laptop is +5V ring to sleeve. On the K3 it is +7.5V tip
> to sleeve. I assume the audio is on the tip on the laptop and the ring
> on the K3. I've not seen any other comments about this on the reflector,
> but perhaps I have not looked carefully enough.
>
> Why would Elecraft do it this way, so these gaming headsets don't work
> without an ugly crossover adapter? Is there any non-soldering way to
> change the connections on the rear panel Mic jack?
>
> Thanks,
>
> Alan G3XAQ
>

--

Alan Ibbetson
[hidden email]
______________________________________________________________
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David Woolley (E.L)

Re: Using a PC headset with K3, connections reverse at rear MIC jack?

In reply to this post by MontyS

I believe the theory behind PC microphone connections is that the same
connector will work for both dynamic and electret microphones. Dynamic
microphones use mono plugs, which short the "bias". That isn't a
problem as the bias is not a voltage source - it is actually the
drain(?) load on the pre-amplifier in the electret microphone - so quite
a high resistance source. Any DC blocking is assumed to be in the PC.

Electret microphones connect the "bias" by having ring and tipped
connected together.

Electret microphones don't need any real bias, as the electret provides
a permanent electrostatic field.

--
David Woolley
Owner K2 06123.

On 29/10/13 15:22, MontyS wrote:
>
> The rear mic jack is a mono, not stereo, jack. It will short the ring
> and sleeve together. Audio is on the tip, as is the voltage. The mic
> should have a blocking capacitor to isolate the audio from the voltage.
>
> This is standard for every radio I have owned. If a stereo jack is
> used, it would be for PTT, not a separate bias connection.
>

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Don Wilhelm-4

Re: Using a PC headset with K3, connections reverse at rear MIC jack?

That statement is only applicable to the actual electret element itself
which has very low output. There are very few bare electret elements
available in the marketplace.

Practical implementation of the electret element uses a built-in
amplifier inside the package that is normally sold as an "electret
microphone element" - that amplifier does need a voltage to operate, but
the current draw is quite low.

73,
Don W3FPR

On 10/29/2013 6:20 PM, David Woolley (E.L) wrote:
> Electret microphones don't need any real bias, as the electret
> provides a permanent electrostatic field.
>

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