[Elecraft] Balanced Mic to Unbalanced Connection Follow Up Question

[Don Wilhelm]

Joe,

I did not say anything to the contrary.  The 'dongle' that I was 
referring to is the connection to pin 1 which should be connected to the 
outside of the K3/K3S enclosure.

73,
Don W3FPR

On 6/9/2020 9:13 PM, Joe Subich, W4TV wrote:
> 
> On 2020-06-09 8:14 PM, Don Wilhelm wrote:
>> So --- make an adapter so that pins 2 and 3 are connected to the tip
>> and ring of the mic jack,
> No, no, no!  The ring of the K3/K3S rear panel mic jack *IS FLOATING*.
> Pins 2 and 3 of the XLR *MUST BE* connected to tip and *SLEEVE*.
> 
> 73,
> 
>     ... Joe, W4TV
> 
> 
> On 2020-06-09 8:14 PM, Don Wilhelm wrote:
>> So --- make an adapter so that pins 2 and 3 are connected to the tip 
>> and ring of the mic jack, then add a one wire 'dongle' exiting from 
>> the XLR plug that is connected to XLR pin 1.  Connect that wire to a 
>> screw on the chassis of the K3/K3S/KX2/KX3.
>>
>> Noise, hum and buzz are  then conducted from the shield onto the 
>> "outside" of the radio enclosure where it should be - avoiding the 
>> "pin 1" problem that K9YC often refers to.
>>
>> For those not familiar with the "pin 1" problem, it is caused by the 
>> jacks in the transceiver (or other gear) being connected to the 
>> circuit board ground plane where it can couple into sensitive circuits 
>> and cause coupling problems.  Proper bonding between enclosures 
>> following the path of audio or coax lines can minimize that problem by 
>> keeping some of the noise, hum and buzz mostly on the outside of the 
>> enclosure rather than injecting it into the circuits on the board 
>> ground plane.
>> We did not have this problem when we mounted the jacks on the 
>> enclosure rather than mounting them on the boards, usually isolated 
>> from the outside of the enclosure.
>>
>> 73,
>> Don W3FPR
>>
>> On 6/9/2020 7:47 PM, Joe Subich, W4TV wrote:
>>>
>>> Correcting *ALL* the typos <G> ....
>>>
>>>
>>>> So which is correct?
>>>
>>> They are electrically equivalent.
>>>
>>> Pin 2 of the XLR connection is Mic+
>>> Pin 3 of the XLR connection is Mic-
>>> Pin 1 of the XLR connection is the cable shield (ground).
>>>
>>> Mic audio is present between pins 2 and 3.
>>>
>>> Pin 1 is nothing more than a shield and should be independently
>>> connected to the *chassis at the jack*.
>>>
>>> Good quality XLR cables use a *TWISTED PAIR* for pins 2 and 3.
>>> That twisted pair is shelf shielding - particularly good for
>>> rejecting hum. Connecting a shield in parallel with the wire
>>> for pin 3 "unbalances" the twisted pair and makes it much
>>> more susceptible to hum and RFI - particularly when the shell
>>> of the 3.5mm plug/jack is not tied to the chassis/case of the
>>> transceiver.
> 
> 
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