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Balanced Mic to Unbalanced Connection Follow Up Question

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Tony-3

Balanced Mic to Unbalanced Connection Follow Up Question

All:

I have a follow-up question regarding balanced mics and unbalanced
connections. I'm about to connect a balanced dynamic microphone (Heil
PR-781) to the rear mic input on my K3S which has a 1/8" unbalanced mono
connection.

One recommendation was to connect XLR pin #2 mic (+) to the tip of the
1/8" jack and pin #3 mic (-) to the sleeve. In this case, pin #1 or
ground is left floating with no connection. A 1/8" mono jack was
recommended for this setup.

The other recommendation was to connect pin #2 to the tip and pin #1 and
#3 to the sleeve of the 1/8" jack. It was also suggested that I can use
either a 1/8" mono or a stereo TRS jack in both cases.

So which is correct?

Tony -K2MO

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Joe Subich, W4TV-4

Re: Balanced Mic to Unbalanced Connection Follow Up Question

> 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 1.

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 1 and 2.
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.

73,

... Joe, W4TV

On 2020-06-09 4:49 PM, Tony wrote:

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Jim Brown-10

Re: Balanced Mic to Unbalanced Connection Follow Up Question

Correcting Joe's typo, Mic audio is present between pins 2 and 3, NOT
between 2 and 1.

73, Jim K9YC

On 6/9/2020 2:54 PM, Joe Subich, W4TV wrote:

>
> > 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 1.
>
> 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 1 and 2.
> 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.

Joe Subich, W4TV-4

Re: Balanced Mic to Unbalanced Connection Follow Up Question

In reply to this post by Tony-3

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.

73,

... Joe, W4TV

On 2020-06-09 4:49 PM, Tony wrote:

Don Wilhelm

Re: Balanced Mic to Unbalanced Connection Follow Up Question

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.

Joe Subich, W4TV-4

Re: Balanced Mic to Unbalanced Connection Follow Up Question

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.

Don Wilhelm

Re: Balanced Mic to Unbalanced Connection Follow Up Question

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.
>
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]

Nr4c

Re: Balanced Mic to Unbalanced Connection Follow Up Question

In reply to this post by Tony-3

If yuh ou use a TRS plug, don’t use the “ring” for anything.

Extending the pin 1 wire out of the connector and connecting to the radio “Ground” lug is also tecvonended in some circles.

Sent from my iPhone
...nr4c. bill

> On Jun 9, 2020, at 4:51 PM, Tony <[hidden email]> wrote:
>
> All:
>
> I have a follow-up question regarding balanced mics and unbalanced connections. I'm about to connect a balanced dynamic microphone (Heil PR-781) to the rear mic input on my K3S which has a 1/8" unbalanced mono connection.
>
> One recommendation was to connect XLR pin #2 mic (+) to the tip of the 1/8" jack and pin #3 mic (-) to the sleeve. In this case, pin #1 or ground is left floating with no connection. A 1/8" mono jack was recommended for this setup.
>
> The other recommendation was to connect pin #2 to the tip and pin #1 and #3 to the sleeve of the 1/8" jack. It was also suggested that I can use either a 1/8" mono or a stereo TRS jack in both cases.
>
> So which is correct?
>
> Tony -K2MO
>
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]

Bob McGraw - K4TAX

Re: Balanced Mic to Unbalanced Connection Follow Up Question

Since the input is clearly marked MONO, a tip-sleeve is the correct plug. If one uses a TRS plug, the ring should be connected to the sleeve inside the plug.

Using a mike which has an XLR, pin 2 should connect to the Tip, pin 3 to the sleeve, and the shield only connects to XLR pin 1 at the mike. It does not connect to the sleeve at the radio.

Bob, K4TAX

Sent from my iPhone

> On Jun 9, 2020, at 10:20 PM, Nr4c <[hidden email]> wrote:
>
> If yuh ou use a TRS plug, don’t use the “ring” for anything.
>
> Extending the pin 1 wire out of the connector and connecting to the radio “Ground” lug is also tecvonended in some circles.
>
> Sent from my iPhone
> ...nr4c. bill
>
>
>> On Jun 9, 2020, at 4:51 PM, Tony <[hidden email]> wrote:
>>
>> All:
>>
>> I have a follow-up question regarding balanced mics and unbalanced connections. I'm about to connect a balanced dynamic microphone (Heil PR-781) to the rear mic input on my K3S which has a 1/8" unbalanced mono connection.
>>
>> One recommendation was to connect XLR pin #2 mic (+) to the tip of the 1/8" jack and pin #3 mic (-) to the sleeve. In this case, pin #1 or ground is left floating with no connection. A 1/8" mono jack was recommended for this setup.
>>
>> The other recommendation was to connect pin #2 to the tip and pin #1 and #3 to the sleeve of the 1/8" jack. It was also suggested that I can use either a 1/8" mono or a stereo TRS jack in both cases.
>>
>> So which is correct?
>>
>> Tony -K2MO
>>
>>
>> ______________________________________________________________
>> 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
>> Message delivered to [hidden email]
> ______________________________________________________________
> 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
> Message delivered to [hidden email]

Gil Drynan

Re: Balanced Mic to Unbalanced Connection Follow Up Question

In reply to this post by Tony-3

The PR-781 does not like the DC bias supplies from many newer ham radios.
A capacitor in series with one side of the balanced line. Heil offers a
specialized cable for three pin XLR mike to the mike jack on front of
different brands of transceivers. Contains the capacitor as required.
Works for me.

Gil W7GIL

> All:
>
> I have a follow-up question regarding balanced mics and unbalanced
> connections. I'm about to connect a balanced dynamic microphone (Heil
> PR-781) to the rear mic input on my K3S which has a 1/8" unbalanced mono
> connection.
>
> One recommendation was to connect XLR pin #2 mic (+) to the tip of the
> 1/8" jack and pin #3 mic (-) to the sleeve. In this case, pin #1 or
> ground is left floating with no connection. A 1/8" mono jack was
> recommended for this setup.
>
> The other recommendation was to connect pin #2 to the tip and pin #1 and
> #3 to the sleeve of the 1/8" jack. It was also suggested that I can use
> either a 1/8" mono or a stereo TRS jack in both cases.
>
> So which is correct?
>
> Tony -K2MO
>
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>

Joe Subich, W4TV-4

Re: Balanced Mic to Unbalanced Connection Follow Up Question

> A capacitor in series with one side of the balanced line.

First, a dynamic mic element as is found in the PR-781 is neither
balanced nor unbalanced. That is determined by the external
connections (the input circuit to which the mic element is
connected). I know of no current amateur transceiver that has a
truly *balanced* microphone input. However, professional and
semiprofessional audio mixers (as well as "effects processors",
microphone equalizers and mic preamps) often have balanced
microphone inputs.

Second, a capacitor is not needed with the Elecraft K3/K3S - one
simply needs to *TURN OFF BIAS* (MENU:MIC SEL and tap #2).

The capacitor is only required for "Brand I" radios in which one
can not turn off the bias.

73,

... Joe, W4TV

On 2020-06-10 10:05 AM, Gil Drynan wrote:

>
> The PR-781 does not like the DC bias supplies from many newer ham radios.
> A capacitor in series with one side of the balanced line. Heil offers a
> specialized cable for three pin XLR mike to the mike jack on front of
> different brands of transceivers. Contains the capacitor as required.
> Works for me.
>
> Gil W7GIL
>
>
>
>
>> All:
>>
>> I have a follow-up question regarding balanced mics and unbalanced
>> connections. I'm about to connect a balanced dynamic microphone (Heil
>> PR-781) to the rear mic input on my K3S which has a 1/8" unbalanced mono
>> connection.
>>
>> One recommendation was to connect XLR pin #2 mic (+) to the tip of the
>> 1/8" jack and pin #3 mic (-) to the sleeve. In this case, pin #1 or
>> ground is left floating with no connection. A 1/8" mono jack was
>> recommended for this setup.
>>
>> The other recommendation was to connect pin #2 to the tip and pin #1 and
>> #3 to the sleeve of the 1/8" jack. It was also suggested that I can use
>> either a 1/8" mono or a stereo TRS jack in both cases.
>>
>> So which is correct?
>>
>> Tony -K2MO
>>

Rich-4

Re: Balanced Mic to Unbalanced Connection Follow Up Question

In reply to this post by Don Wilhelm

Interesting stuff here. Since the original post was regarding the Rear
Mic jack. Would this method also be recommended for the Front Panel
Mic Jack also?

My guess is yes

Rich

K3RWN

On 6/9/2020 22:50 PM, Don Wilhelm wrote:

> 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.
>>
>>
>> ______________________________________________________________
>> 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
>> Message delivered to [hidden email]
> ______________________________________________________________
> 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
> Message delivered to [hidden email]

Bob McGraw - K4TAX

Re: Balanced Mic to Unbalanced Connection Follow Up Question

I use a Shure SM-58 mike with my K3S. It is a balanced dynamic mike.

It has an XLR at the mike and the 8 pin Foster connector at the radio.
I use good quality, 2 conductor, shielded mike cable.

It is wired as follows:

XLR pin #1 to Foster pin #8 {shield}

XLR pin #2 to Foster pin #1 {black}

XLR pin #3 to Foster pin#7 {white}

Operating 160M - 6M at 500 watts or less, I find no issues with the
wiring convention as it works very satisfactory.

73

Bob, K4TAX

On 6/11/2020 8:15 AM, Rich wrote:

> Interesting stuff here.   Since the original post was regarding the
> Rear Mic jack.   Would this method also be recommended for the Front
> Panel Mic Jack also?
>
> My guess is yes
>
> Rich
>
> K3RWN
>
> On 6/9/2020 22:50 PM, Don Wilhelm wrote:
>> 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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Tony-3

Re: Balanced Mic to Unbalanced Connection Follow Up Question

In reply to this post by Tony-3

All:

The K3S seems to work flawlessly with XLR cable connected to the rear
panel mic input as per the groups recommendations. I have pins 1 and 3
connected to the sleeve of the 1/8" plug and pin 2 to the tip. I'm using
a dynamic mic so the bias is turned off. This setup works fine on the
KX3 as well.

If anyone is interested, I have a brand new Heil XLR cable for the K3S
that I won't be using.

Thanks,

Tony -K2MO

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N7US

Re: Balanced Mic to Unbalanced Connection Follow Up Question

I have a microHAM microKEYER III that I use with my K3S. I have a Heil
HM-10 Dual mic, which uses the Heil cable with an XLR connector, and a Heil
headset, which has a 3.5mm phone plug. Both connect to the MKIII, which
connects to the rear mic jack on the K3S, and it's easy to switch between
the two using the microHAM router software.

Jim N7US

-----Original Message-----
From: [hidden email] <[hidden email]> On
Behalf Of Tony
Sent: Thursday, June 11, 2020 20:01
To: [hidden email]
Subject: Re: [Elecraft] Balanced Mic to Unbalanced Connection Follow Up
Question

All:

The K3S seems to work flawlessly with XLR cable connected to the rear panel
mic input as per the groups recommendations. I have pins 1 and 3 connected
to the sleeve of the 1/8" plug and pin 2 to the tip. I'm using a dynamic mic
so the bias is turned off. This setup works fine on the
KX3 as well.

If anyone is interested, I have a brand new Heil XLR cable for the K3S that
I won't be using.

Thanks,

Tony -K2MO

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Bob McGraw - K4TAX

Re: Balanced Mic to Unbalanced Connection Follow Up Question

In reply to this post by Tony-3

Tony;

Seems you have done an excellent job and things are working as you
expected. And a special thanks to you for reporting back to the group
your findings and results. I wish everyone did that. We'd all be
informed.

73

Bob, K4TAX

On 6/11/2020 8:00 PM, Tony wrote:

> All:
>
> The K3S seems to work flawlessly with XLR cable connected to the rear
> panel mic input as per the groups recommendations. I have pins 1 and 3
> connected to the sleeve of the 1/8" plug and pin 2 to the tip. I'm
> using a dynamic mic so the bias is turned off. This setup works fine
> on the KX3 as well.
>
> If anyone is interested, I have a brand new Heil XLR cable for the K3S
> that I won't be using.
>
> Thanks,
>
> Tony -K2MO
>
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]

Tony-3

Re: Balanced Mic to Unbalanced Connection Follow Up Question

On 6/11/2020 10:16 PM, Bob McGraw K4TAX wrote:

> a special thanks to you for reporting back to the group your findings
> and results.

Thanks for your input as well Bob. Lots of talented folks on the
reflector who take the time to respond to questions. The least one can
do is provide feedback.

Tony -K2MO

> Tony;
>
> Seems you have done an excellent job and things are working as you
> expected. And a special thanks to you for reporting back to the
> group your findings and results. I wish everyone did that. We'd all
> be informed.
>
> 73
>
> Bob, K4TAX
>
>
> On 6/11/2020 8:00 PM, Tony wrote:
>> All:
>>
>> The K3S seems to work flawlessly with XLR cable connected to the rear
>> panel mic input as per the groups recommendations. I have pins 1 and
>> 3 connected to the sleeve of the 1/8" plug and pin 2 to the tip. I'm
>> using a dynamic mic so the bias is turned off. This setup works fine
>> on the KX3 as well.
>>
>> If anyone is interested, I have a brand new Heil XLR cable for the
>> K3S that I won't be using.
>>
>> Thanks,
>>
>> Tony -K2MO
>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> 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
>> Message delivered to [hidden email]
>
> ______________________________________________________________
> Elecraft mailing list
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>
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> Message delivered to [hidden email]