[Elecraft] MD2 resistor mod - a different approach?

[Tom Althoff]

That's even better..no cutting of lands on the control board as I would have
had to do.

Thanks once again Don!

And Happy Thankgiving to all on the reflector.

73 de Tom K2TA
K2 #1117-C

----- Original Message ----- 
From: "W3FPR - Don Wilhelm" <w3fpr at earthlink.net>
To: "Tom Althoff" <althoff at verizon.net>; "Elecraft"
<elecraft at mailman.qth.net>
Sent: Tuesday, November 23, 2004 9:17 PM
Subject: Re: [Elecraft] MD2 resistor mod - a different approach?


> Tom and all,
>
> There is a solution to using a mic requiring the 5 volts (through a
> resistor) and switching to a mic that does not need it which does NOT
> require the resistor to be in the mic plug.
>
> Wire the resistor at the mic jack between pins 5 and 6 (pin 5 = FUNC which
> is not used), then in the mic plug for the microphone(s) needing the 5
> volts, add a jumper from pin 5 to pin 1.  The mic jack will have only AF
on
> pin 1, and will have +5 volts through the resistor on pin 5.
>
> When wired this way, your Elecraft mic will work on other K2s wired for
the
> standard Elecraft mic, but another standard Elecraft mic will not work on
> your K2.
>
> Additional note - if NONE of your mics have the UP and DOWN buttons
> implemented, you can use pins 3 and 4 for any purpose you wish - including
> piping the +5 volts on one of these pins instead of pin 5.
>
> 73,
> Don W3FPR
>
>
> ----- Original Message ----- 
>
> I want to be able to switch between my MD2 mic which needs DC applied to
the
> AF line and my Heil Proset Plus headset which doesn't.
>
> I'm not sure I could fit the resistor that comes with the MD2 inside the
> female connector at the mic side so I'm looking into connecting pins 6 and
1
> together in the female mic connector and putting the resistor in  SERIES
> with the 5 VDC line going to pin 6 at the male end of the jack.
>
> When the MD2 is plugged in the AF line would get DC applied through the
> dropping resistor in the 5 volt line.   When I plug in the Proset Plus pin
1
> is just audio and no DC applied.
>
> Does anyone see a problem with doing it this way?   I know you won't be
able
> to pull a lot from the 5 volt line after this mod but I don't plan on
> powering anything else off of the mic connector.    Also...I would not be
> able to plug my mic into someone else's K2 as it would put the unlimited
> 5VDC line directly to my mic element.   I practice safe microphoning and
> never insert my mic into any other K2 except my own so I'm not concerned
in
> either case.
>
> Comments?  Suggestions?
>
> Tom K2TA
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