K2: KSB2 Questions

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K2: KSB2 Questions

Paul Huff-3
I am almost exclusively a CW guy but I did purchase the KSB2 option with my K2
for some soundcard digital modes.  I finished the board almost a year ago but
have never gotten around to installing it yet.  (It's very hard to pull me away
from CW!)  Well I'm now thinking about installing it and I have a few
questions...

1.  I know that there is a rework eliminator that lets you easily change
microphone configurations but that seems like overkill to me since I will
probably never actually operate SSB after the initial testing.  So a simple
connector for the 16-pins of P1, wired up with the appropriate jumper
connections, makes sense.  But I don't know what kind of connector I need for
this.  A look at the Mouser catalog was overwhelming with the huge number of
different connectors available!  What kind of connector do I need to get?  Is
there any chance that I can find it locally at a Radio Shack or computer store
instead of ordering it?  BTW, an editorial comment - I'm surprised that Elecraft
doesn't provide this connector with the KSB2!

2.  This may be a silly question, but I would rather ask a silly question than
make a silly mistake!  Do the filter adjustments that I need to make for the
KSB2 have any impact on the ones that I have already made for my CW work?  I
worked very hard to optimize those settings and I would really hate to mess them
up!

3.  Another possibly silly question.  The ICOM microphone that I will be using
requires a 10K bias resistor between the 5 volt and AF pins.  Will this bias
resistor have any impact on the connections that I will eventually need to make
between my computer and the microphone jack for digital mode work?

Thanks in advance for any information that you can share!

73,
Paul - N8XMS

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Re: K2: KSB2 Questions

Don Wilhelm-4
  Paul,

I just got back from three days vacation, and found 226 emails on the
reflector!  I finally waded through them and will attempt to answer a
few, including yours.

First, how to connect to the microphone configuration header - if you
are wiring it for the Elecraft configuration, just use computer jumpers,
all pins are connected "straight across"
But, you said you were using an ICOM mic which is wired differently, so
you have two choices, (1) rewire the microphone plug to match the
Elecraft configuration, and tape over the Icom label so you remember it
was changed (I recommend that because the microphone can then be used on
the K3, and any Elecraft microphone can be used with the K2).  (2) Leave
the microphone plug as it is and wire the K2 mic configuration header
for the Icom pinout.  The best way to do that is using wire-wrap (if you
have the tool and wire), and the second best is soldering wires between
the correct pins.  There is no plug for this connector, the header is
designed to be wired directly.  The only downside of soldering is that
one cannot remove the soldered wires and go back to using the
computer-type jumpers.

Solder the bias resistor on the back of the microphone jack rather than
trying to connect it at the configuration header.  A value from 5.6k to
10k will work fine for most electret mics like the Icom and the Elecraft
mics.  one end of the resistor connects to the 5 volt mic jack pin and
the other end connects to the AF pin.

Yes, that bias resistor MAY cause some problems with the soundcard
line-out for SOME soundcards.  It would be wise to put a DC Blocking
capacitor in the AF line of whatever soundcard interface you may use if
there is not one there already.

73,
Don W3FPR

On 4/6/2011 10:14 AM, Paul Huff wrote:

> I am almost exclusively a CW guy but I did purchase the KSB2 option with my K2
> for some soundcard digital modes.  I finished the board almost a year ago but
> have never gotten around to installing it yet.  (It's very hard to pull me away
> from CW!)  Well I'm now thinking about installing it and I have a few
> questions...
>
> 1.  I know that there is a rework eliminator that lets you easily change
> microphone configurations but that seems like overkill to me since I will
> probably never actually operate SSB after the initial testing.  So a simple
> connector for the 16-pins of P1, wired up with the appropriate jumper
> connections, makes sense.  But I don't know what kind of connector I need for
> this.  A look at the Mouser catalog was overwhelming with the huge number of
> different connectors available!  What kind of connector do I need to get?  Is
> there any chance that I can find it locally at a Radio Shack or computer store
> instead of ordering it?  BTW, an editorial comment - I'm surprised that Elecraft
> doesn't provide this connector with the KSB2!
>
> 2.  This may be a silly question, but I would rather ask a silly question than
> make a silly mistake!  Do the filter adjustments that I need to make for the
> KSB2 have any impact on the ones that I have already made for my CW work?  I
> worked very hard to optimize those settings and I would really hate to mess them
> up!
>
> 3.  Another possibly silly question.  The ICOM microphone that I will be using
> requires a 10K bias resistor between the 5 volt and AF pins.  Will this bias
> resistor have any impact on the connections that I will eventually need to make
> between my computer and the microphone jack for digital mode work?
>
> Thanks in advance for any information that you can share!
>
> 73,
> Paul - N8XMS
>
> ______________________________________________________________
> 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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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Please help support this email list: http://www.qsl.net/donate.html