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From: "Randy Hargenrader" <randyh at harksystems.com>
Subject: [Elecraft] Computer headsets

Gang,

I found that all the computer headsets I tested were wired
the same way, (whatever that is, I don't remember if the
tip is mic or not...) and I made an adapter using an inline
stereo jack that the headset can plug into.  I also wired a 
push button switch for PTT.  Theres also a version of them
that have two plugs, one for the earphone and one for the 
microphone.  In fact, now that I think of it, most of mine have
the two plug arrangement.

The nice thing about the jack arrangement is I was able to
test headsets very easily to find which one had the best 
transmit audio (believe me!  there's a BIG difference from
one model to the next!).  Another advantage is that I can 
have one headset for use at the home QTH with the bulky
but comfortable ear-pieces or the little slim-line/hang on 
your ear/small profile/takes up no space/easy to pack version
for the field trips.

Being a male it's hard for me to make a commitment so I didn't
want to hard wire the headsets into the connectors.  And there
seems to be an inexhaustable supply of headsets to test.  (So
many headsets, so little time.) Oh, and since they are for the 
computer market- they are all very inexpensive.

Since the microphones in them are electrocet, they require a
voltage source.  I wired a 10K ohm inside the K2 to put 5 volts
on the "mic audio" pin.  I guess this could be done in the barrel
of the connector as well since there is a pin for 5VDC on the
mic connector.

72,
Randy WJ4P

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Date: Fri, 8 Mar 2002 20:23:57 -0600
From: George Franklin <w0av at juno.com>
To: qrp-l at lehigh.edu
Subject: [121648] Ref. El Cheapo  Headset for K2

Hi Fellow K2ers,

If you have wanted to use a headset for SSB but didn't want to spend $50
to $100 bucks here is an inexpensive way to go.

Radio Shack has currently on sale (half price) computer headset PN
33-1107 for $9.98.
Other headsets would very likely work just as well, but I haven't tried
any except this one.

Add a tantalum cap (I used 0.1uF) and a resistor (I used a 560 ohm 1/4 W)
inside the RS 8-pin mike plug (PN 274-025) and you have an excellent
headset for about $15.00.

Use the 3.5mm plug as is into the K2 headphone jack.

Cut off the 2.5mm (mike) plug and wire the RS 8-pin as follows:

                           A.  Mike lead through the tantalum cap to pin
1 on the 8-pin.
                                          (positive side of cap to mike
side of the cap)
                           B.  The resistor must connect (inside the 8-pin connector housing) to the
mike side of the tantalum capacitor, NOT TO PIN ONE (which is the radio
side).

The resistor is obviously required to provide operating voltage for the
electret microphone element and must therefore be connected as above.

                           C.  Shield to pin 7 of 8-pin

The above assumes you have wired your K2 to be "Kenwood compatible."
If not, consult your K2 manual for proper pins to use.
 
Be sure to insulate the components with plastic tape before sliding them
inside the 8-pin plugs housing to avoid shorts.

I've been receiving glowing TX audio reports and the K2 RX audio sounds
great.

A friend told me my Heil Gold Line mike (which I normally used) really
sounded great on the K2.  Then I told him it was the el cheapo unit!

This setup keys the K2's VOX very nicely.

Try it; you'll like it.

FWIW.

72/73/74 de George/W0AV
Hamming since '35
SOC#101, COG#1, PITA (# TBA)

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