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Using GM-5 Mic with K2

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Roy Morris-6

Using GM-5 Mic with K2

I would like to know if the CC1-K cable connects the 5v on pin #6 from the
K2 to pin #6 on the GM-5 creating an unwanted bias. There is a 4 pin mic
connection on the CC1-K the GM-5 plugs into. Does one of these 4 pins
supply bias to the GM-5? Thanks, Roy W4WFB

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Joe Subich, W4TV-4

Re: Using GM-5 Mic with K2

> I would like to know if the CC1-K cable connects the 5v on pin #6
> from the K2 to pin #6 on the GM-5 creating an unwanted bias.

No.

> There is a 4 pin mic connection on the CC1-K the GM-5 plugs into.
> Does one of these 4 pins supply bias to the GM-5?

No. The fourth pin is PTT.

73,

... Joe, W4TV

On 8/16/2011 4:06 PM, Roy Morris wrote:

> I would like to know if the CC1-K cable connects the 5v on pin #6 from the
> K2 to pin #6 on the GM-5 creating an unwanted bias. There is a 4 pin mic
> connection on the CC1-K the GM-5 plugs into. Does one of these 4 pins
> supply bias to the GM-5? Thanks, Roy W4WFB
>
> ______________________________________________________________
> Elecraft mailing list
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Joe Subich, W4TV-4

Re: Using GM-5 Mic with K2

> Thanks, Joe. It seems to me that a 5.6K resistor between pins #1 and
> #6 on the K2 front panel mic connector would create bias on the pin
> #1 mic line that would carry over to GM-5 pin #1 mic line.

Yes, if you have bias on pin 1 it will appear on the mic. You did not
ask that question - you asked if pin 6 was connected in the CC-1K.

> I am looking for a way to use the GM-5 as well. I am going to somehow
> have to eliminate bias from pin #1 when I use the GM-5. I think I
> might be able to do this by connecting the 5.6K resistor between pins
> 5 and 6 on the K2 front panel mic connector and connect pins 1 and 5
> together on the electret mic plugs.

The 5.6K resistor is a user option:
1) you can remove it to eliminate the bias for the GM5
2) or you can add a 1 uF cap in the CC-1K - in series with pin 1 on
Foster end or in series with pin 2 on the XLR end. I'd suggest
checking pin 1 to pin 2 for a DC connection but the information
I have suggests that there is no capacitor in the Heil cables
for Yaesu or Kenwood - my information is that only the CC-1I
has a blocking capacitor.
3) you can install 5.6K resistors between pin 1 and pin 6 in the
mic connectors on your electret mics.
4) you can check to see if there is DC continuity between pin 1 and
pin 2 of the GM-5. If Heil has done it right they have installed
a 1 to 10 uF cap in series with pin 2 of the GM-5 (pin 1 = mic
return/shield, pin 2 = mic "hot", pin 3/4 = PTT switch) to block
DC.

73,

... Joe, W4TV

On 8/16/2011 5:24 PM, Roy Morris wrote:

> Thanks, Joe. It seems to me that a 5.6K resistor between pins #1 and #6
> on the K2 front panel mic connector would create bias on the pin #1 mic
> line that would carry over to GM-5 pin #1 mic line. This resistor is
> needed to supply bias for the MD2 and MH2 electret mics. I am looking
> for a way to use the GM-5 as well. I am going to somehow have to
> eliminate bias from pin #1 when I use the GM-5. I think I might be able
> to do this by connecting the 5.6K resistor between pins 5 and 6 on the
> K2 front panel mic connector and connect pins 1 and 5 together on the
> electret mic plugs. This should keep bias off the GM-5 if pin #6 is not
> used with the CC-1K.
> The only problem I see is that pin #5 is a function line and in effect
> is a floating ground.
>
> ----- Original Message ----- From: "Joe Subich, W4TV" <[hidden email]>
> To: "Roy Morris" <[hidden email]>; "Elecraft Reflector"
> <[hidden email]>
> Sent: Tuesday, August 16, 2011 4:45 PM
> Subject: Re: [Elecraft] Using GM-5 Mic with K2
>
>
>>
>>> I would like to know if the CC1-K cable connects the 5v on pin #6
>>> from the K2 to pin #6 on the GM-5 creating an unwanted bias.
>>
>> No.
>>
>>> There is a 4 pin mic connection on the CC1-K the GM-5 plugs into.
>>> Does one of these 4 pins supply bias to the GM-5?
>>
>> No. The fourth pin is PTT.
>>
>> 73,
>>
>> ... Joe, W4TV
>>
>>
>> On 8/16/2011 4:06 PM, Roy Morris wrote:
>>> I would like to know if the CC1-K cable connects the 5v on pin #6
>>> from the
>>> K2 to pin #6 on the GM-5 creating an unwanted bias. There is a 4 pin mic
>>> connection on the CC1-K the GM-5 plugs into. Does one of these 4 pins
>>> supply bias to the GM-5? Thanks, Roy W4WFB
>>>
>>> ______________________________________________________________
>>> 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
>>>
>
>

Don Wilhelm-4

Re: Using GM-5 Mic with K2

Roy,

If you implement your "pin 5, pin 6" solution, remove the jumper for pin
5 from the microphone configuration header. There is no function in the
K2 for the Function line, but it should not have voltage applied to it
inside the K2.

Then in each mic connector, wire between pin 5 and pin 1 for any
microphone that wants bias. Also check all other mics and adapters to
be certain there is nothing wired to either pin 5 or pin 6.

73,
Don W3FPR

On 8/16/2011 6:03 PM, Joe Subich, W4TV wrote:

>> Thanks, Joe. It seems to me that a 5.6K resistor between pins #1 and
>> #6 on the K2 front panel mic connector would create bias on the pin
>> #1 mic line that would carry over to GM-5 pin #1 mic line.
> Yes, if you have bias on pin 1 it will appear on the mic. You did not
> ask that question - you asked if pin 6 was connected in the CC-1K.
>
>> I am looking for a way to use the GM-5 as well. I am going to somehow
>> have to eliminate bias from pin #1 when I use the GM-5. I think I
>> might be able to do this by connecting the 5.6K resistor between pins
>> 5 and 6 on the K2 front panel mic connector and connect pins 1 and 5
>> together on the electret mic plugs.
> The 5.6K resistor is a user option:
> 1) you can remove it to eliminate the bias for the GM5
> 2) or you can add a 1 uF cap in the CC-1K - in series with pin 1 on
> Foster end or in series with pin 2 on the XLR end. I'd suggest
> checking pin 1 to pin 2 for a DC connection but the information
> I have suggests that there is no capacitor in the Heil cables
> for Yaesu or Kenwood - my information is that only the CC-1I
> has a blocking capacitor.
> 3) you can install 5.6K resistors between pin 1 and pin 6 in the
> mic connectors on your electret mics.
> 4) you can check to see if there is DC continuity between pin 1 and
> pin 2 of the GM-5. If Heil has done it right they have installed
> a 1 to 10 uF cap in series with pin 2 of the GM-5 (pin 1 = mic
> return/shield, pin 2 = mic "hot", pin 3/4 = PTT switch) to block
> DC.
>
> 73,
>
> ... Joe, W4TV
>
>
>
> On 8/16/2011 5:24 PM, Roy Morris wrote:
>> Thanks, Joe. It seems to me that a 5.6K resistor between pins #1 and #6
>> on the K2 front panel mic connector would create bias on the pin #1 mic
>> line that would carry over to GM-5 pin #1 mic line. This resistor is
>> needed to supply bias for the MD2 and MH2 electret mics. I am looking
>> for a way to use the GM-5 as well. I am going to somehow have to
>> eliminate bias from pin #1 when I use the GM-5. I think I might be able
>> to do this by connecting the 5.6K resistor between pins 5 and 6 on the
>> K2 front panel mic connector and connect pins 1 and 5 together on the
>> electret mic plugs. This should keep bias off the GM-5 if pin #6 is not
>> used with the CC-1K.
>> The only problem I see is that pin #5 is a function line and in effect
>> is a floating ground.
>>
>> ----- Original Message ----- From: "Joe Subich, W4TV"<[hidden email]>
>> To: "Roy Morris"<[hidden email]>; "Elecraft Reflector"
>> <[hidden email]>
>> Sent: Tuesday, August 16, 2011 4:45 PM
>> Subject: Re: [Elecraft] Using GM-5 Mic with K2
>>
>>
>>>> I would like to know if the CC1-K cable connects the 5v on pin #6
>>>> from the K2 to pin #6 on the GM-5 creating an unwanted bias.
>>> No.
>>>
>>>> There is a 4 pin mic connection on the CC1-K the GM-5 plugs into.
>>>> Does one of these 4 pins supply bias to the GM-5?
>>> No. The fourth pin is PTT.
>>>
>>> 73,
>>>
>>> ... Joe, W4TV
>>>
>>>
>>> On 8/16/2011 4:06 PM, Roy Morris wrote:
>>>> I would like to know if the CC1-K cable connects the 5v on pin #6
>>>> from the
>>>> K2 to pin #6 on the GM-5 creating an unwanted bias. There is a 4 pin mic
>>>> connection on the CC1-K the GM-5 plugs into. Does one of these 4 pins
>>>> supply bias to the GM-5? Thanks, Roy W4WFB
>>>>
>>>> ______________________________________________________________
>>>> 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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>

Roy Morris-6

Re: Using GM-5 Mic with K2

In reply to this post by Roy Morris-6

Hello Don,
Thanks for the suggestion to remove the jumper from the K2 header to remove
the function circuit which will give me a "clean" pin #5 to use. I should
then be able to interchange my MD2, MH2 and GM-5 mics without worrying about
the bias line. Thanks again. 73, Roy W4WFB

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