K2 Why MH2 mic seems dead

[k7nhb]

I've been reading posts about the MH2 mic and have had my own struggles with it. Is it common knowledge that the mic pickup element is only effective when talking into the top scree on the mic? If I talk into the front screen with SSBA at 1, it doesn't pick up a think. When I set SSBA to 2 or 3 is does pick up audio but I think that's because it is so sensitive it is also picking it up from the top.

When I opened the mic, I saw the mic element in foam, in a compartment below the top screen and practically isolated from the screen if front of the mic. In fact, that front screen looked like it was just a plastic facade.

Is that how mics are suppose to be made? My only guess is, by putting the capture area on top, it avoids speaking directly into the mic if you are expecting it to pick up via the front screen.

I have that 600 ohm dynamic Kenwood mic that is often used with the SGC-2020 (up/down buttons on top). I thought about replacing the MH2 with it - mainly because its slimmer profile would allow it to fit in the Pelican case with the K2.

Can someone tell me it that Kenwood would be a direct replacement or would I have to rewire something. It doesn't have a model number on it but I think it is MC-43s. What about audio quality - the K2 is only the QRP-ish model.

Thank you and 73,
Paul K7NHB

[Don Wilhelm-4]

Paul,

You apparently did not get my private email to you.

You are talking about the older MH2 microphone made by Heil - if it has
the Heil name on the front and the Elecraft MH2 label on the back, it is
one of those.  The current (for many years now) Elecraft MH2 microphones
are different, and have the Elecraft name on the front.

Yes, that microphone can be messed up inside - Heil used another
microphone and modified it - on mine, the original dynamic element was
clipped out, turned around and inserted into the hole for it. There is
another front facing hole more toward the top where it electret element
is supposed to be located - it should face the front, not the top.  That
element is secured with just a bit of foam, so I can understand how
yours may have tilted out of place.
Heil no longer supplies the MH2 microphone to Elecraft and you can
probably guess why.  There are only a few hundred MH2 microphones that
were built by Heil, and more like thousands that were built to Elecraft
specifications.

So turn your electret element so it faces the front and it should be
OK.  To reassemble it, dress the wires properly in the slots and squeeze
the tabs on the PTT button so you can move it outward into a "parking"
position while you put the back on (if you do not do that, the PTT
button will bind).

Your K2 has the Rework Eliminators Internal Microphone Adapter
installed, so changing microphone types is as easy as removing the left
side panel and change the plugs.  Refer to the IMA manual from Rework
Eliminators (or unpcbs) - That in not an Elecrraft add-on.

The Elecraft microphones require bias (the 5.6k resistor in the IMA),
but dynamic microphones do not.  Again refer to the IMA plugging
instructions from http://www.unpcbs.com/adaptor/adaptor_pdfs/ima_ug.pdf


73,
Don W3FPR


On 6/28/2013 3:22 PM, k7nhb wrote:

> I've been reading posts about the MH2 mic and have had my own struggles with
> it. Is it common knowledge that the mic pickup element is only effective
> when talking into the top scree on the mic? If I talk into the front screen
> with SSBA at 1, it doesn't pick up a think. When I set SSBA to 2 or 3 is
> does pick up audio but I think that's because it is so sensitive it is also
> picking it up from the top.
>
> When I opened the mic, I saw the mic element in foam, in a compartment below
> the top screen and practically isolated from the screen if front of the mic.
> In fact, that front screen looked like it was just a plastic facade.
>
> Is that how mics are suppose to be made? My only guess is, by putting the
> capture area on top, it avoids speaking directly into the mic if you are
> expecting it to pick up via the front screen.
>
> I have that 600 ohm dynamic Kenwood mic that is often used with the SGC-2020
> (up/down buttons on top). I thought about replacing the MH2 with it - mainly
> because its slimmer profile would allow it to fit in the Pelican case with
> the K2.
>
> Can someone tell me it that Kenwood would be a direct replacement or would I
> have to rewire something. It doesn't have a model number on it but I think
> it is MC-43s. What about audio quality - the K2 is only the QRP-ish model.
>
> Thank you and 73,
> Paul K7NHB
>
>
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/K2-Why-MH2-mic-seems-dead-tp7575961.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
> 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
>

______________________________________________________________
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

[Eugene Balinski]

Electret Condenser mic elements are typically very
sensitive to their mounting location.  A small movement the
element can make a huge difference in the sound. You may
get better performance if you move the element to the front
of the foam directly to the rear of the mic screen...

73
Gene K1NR

  On Fri, 28 Jun 2013 12:22:24 -0700 (PDT)
 k7nhb <[hidden email]> wrote:

> I've been reading posts about the MH2 mic and have had my
> own struggles with
> it. Is it common knowledge that the mic pickup element is
> only effective
> when talking into the top scree on the mic? If I talk
> into the front screen
> with SSBA at 1, it doesn't pick up a think. When I set
> SSBA to 2 or 3 is
> does pick up audio but I think that's because it is so
> sensitive it is also
> picking it up from the top.
>
> When I opened the mic, I saw the mic element in foam, in
> a compartment below
> the top screen and practically isolated from the screen
> if front of the mic.
> In fact, that front screen looked like it was just a
> plastic facade.
>
> Is that how mics are suppose to be made? My only guess
> is, by putting the
> capture area on top, it avoids speaking directly into the
> mic if you are
> expecting it to pick up via the front screen.
>
> I have that 600 ohm dynamic Kenwood mic that is often
> used with the SGC-2020
> (up/down buttons on top). I thought about replacing the
> MH2 with it - mainly
> because its slimmer profile would allow it to fit in the
> Pelican case with
> the K2.
>
> Can someone tell me it that Kenwood would be a direct
> replacement or would I
> have to rewire something. It doesn't have a model number
> on it but I think
> it is MC-43s. What about audio quality - the K2 is only
> the QRP-ish model.
>
> Thank you and 73,
> Paul K7NHB
>
>
>
> --
> View this message in context:
>

http://elecraft.365791.n2.nabble.com/K2-Why-MH2-mic-seems-dead-tp7575961.html
> Sent from the Elecraft mailing list archive at
> Nabble.com.
>
______________________________________________________________
> 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

---------------------------------------------------------------------
Web mail provided by NuNet, Inc. The Premier National provider.
http://www.nni.com/
______________________________________________________________
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