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[KX3] Using a Sound Card for Mic (Multiple) Input(s)

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Joel Black-2

[KX3] Using a Sound Card for Mic (Multiple) Input(s)

I am not a professional sound engineer by any stretch of the imagination. I am usually more surprised than anyone else when I get something working. I do, however, have my sound card working for AFSK modes with the KX3. At one point, I thought I wanted a mixer and asked such of this group. I may still go that way but in an effort to keep my station as "minimalist" as possible, I was thinking of a sound card with multiple inputs.

I currently have a Focusrite 2i2 I bought after my E-MU 0204 stopped working in OS X 10.11. It has two inputs and two outputs. Experimenting the other day, I tried using my MH3 mic on the input to the sound card with the sound card output going to the MIC IN on the KX3. It didn’t work. I then realized that the MH3 is a condenser mic and needs to be powered. The 2i2 has a “48 V phantom power” switch, but I am a little nervous of turning that on. I don’t want to let all the “magic smoke” out of my mic.

After all of that, I began remembering an issue I had with a Genesis G59 SDR I built several years ago - the delay in the route from audio in to the sound card, the sound card input being processed by the computer, the computer outputting that data to the transmitter. It was quite reminiscent of my days operating the HEO satellites. The delay is unnerving and I have never been able to compensate for it other than turning off MON. I’m supposing I’ll have the same delay if I incorporate a sound card for multiple inputs.

Would I be better off just adding a mixer?

73,
Joel - W4JBB
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Don Wilhelm

Re: [KX3] Using a Sound Card for Mic (Multiple) Input(s)

Joel,

Ham and consumer "condenser" microphones should not be subjected to 48
volt phantom power. That is for professional microphones which need
that power.
The ham and consumer "condenser" microphones are normally referred to as
"electret" microphones rather than as condenser microphones. Those need
a 5 to 8 volt source applied to the AF lead through a resistor (usually
5K to 10k).

I would recommend using a switch rather than a mixer. You do not want
an open mic when operating digital modes, nor do you usually want the
soundcard connected when using voice signals.
With a hard-wired switch, you can turn the bias on in the MIC SEL menu
when operating voice. If you want to leave bias turned on even though
you are working digital modes, add a series capacitor in the AF line to
the soundcard output.

If you want to use the mixer, I would suggest an audio pro microphone.
If that mic needs phantom power, then turn it on.

73,
Don W3FPR

On 5/28/2016 8:45 AM, Joel Black wrote:

> I am not a professional sound engineer by any stretch of the imagination. I am usually more surprised than anyone else when I get something working. I do, however, have my sound card working for AFSK modes with the KX3. At one point, I thought I wanted a mixer and asked such of this group. I may still go that way but in an effort to keep my station as "minimalist" as possible, I was thinking of a sound card with multiple inputs.
>
> I currently have a Focusrite 2i2 I bought after my E-MU 0204 stopped working in OS X 10.11. It has two inputs and two outputs. Experimenting the other day, I tried using my MH3 mic on the input to the sound card with the sound card output going to the MIC IN on the KX3. It didn’t work. I then realized that the MH3 is a condenser mic and needs to be powered. The 2i2 has a “48 V phantom power” switch, but I am a little nervous of turning that on. I don’t want to let all the “magic smoke” out of my mic.
>
> After all of that, I began remembering an issue I had with a Genesis G59 SDR I built several years ago - the delay in the route from audio in to the sound card, the sound card input being processed by the computer, the computer outputting that data to the transmitter. It was quite reminiscent of my days operating the HEO satellites. The delay is unnerving and I have never been able to compensate for it other than turning off MON. I’m supposing I’ll have the same delay if I incorporate a sound card for multiple inputs.
>
> Would I be better off just adding a mixer?
>
> 73,
> Joel - W4JBB
> ______________________________________________________________
> 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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Joel Black-2

Re: [KX3] Using a Sound Card for Mic (Multiple) Input(s)

Thanks, Don. That’s what I needed to hear.

73,
Joel - W4JBB

> On May 28, 2016, at 15:52, Don Wilhelm <[hidden email]> wrote:
>
> Joel,
>
> Ham and consumer "condenser" microphones should not be subjected to 48 volt phantom power. That is for professional microphones which need that power.
> The ham and consumer "condenser" microphones are normally referred to as "electret" microphones rather than as condenser microphones. Those need a 5 to 8 volt source applied to the AF lead through a resistor (usually 5K to 10k).
>
> I would recommend using a switch rather than a mixer. You do not want an open mic when operating digital modes, nor do you usually want the soundcard connected when using voice signals.
> With a hard-wired switch, you can turn the bias on in the MIC SEL menu when operating voice. If you want to leave bias turned on even though you are working digital modes, add a series capacitor in the AF line to the soundcard output.
>
> If you want to use the mixer, I would suggest an audio pro microphone. If that mic needs phantom power, then turn it on.
>
> 73,
> Don W3FPR
>
> On 5/28/2016 8:45 AM, Joel Black wrote:
>> I am not a professional sound engineer by any stretch of the imagination. I am usually more surprised than anyone else when I get something working. I do, however, have my sound card working for AFSK modes with the KX3. At one point, I thought I wanted a mixer and asked such of this group. I may still go that way but in an effort to keep my station as "minimalist" as possible, I was thinking of a sound card with multiple inputs.
>>
>> I currently have a Focusrite 2i2 I bought after my E-MU 0204 stopped working in OS X 10.11. It has two inputs and two outputs. Experimenting the other day, I tried using my MH3 mic on the input to the sound card with the sound card output going to the MIC IN on the KX3. It didn’t work. I then realized that the MH3 is a condenser mic and needs to be powered. The 2i2 has a “48 V phantom power” switch, but I am a little nervous of turning that on. I don’t want to let all the “magic smoke” out of my mic.
>>
>> After all of that, I began remembering an issue I had with a Genesis G59 SDR I built several years ago - the delay in the route from audio in to the sound card, the sound card input being processed by the computer, the computer outputting that data to the transmitter. It was quite reminiscent of my days operating the HEO satellites. The delay is unnerving and I have never been able to compensate for it other than turning off MON. I’m supposing I’ll have the same delay if I incorporate a sound card for multiple inputs.
>>
>> Would I be better off just adding a mixer?
>>
>> 73,
>> Joel - W4JBB
>> ______________________________________________________________
>> 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]
>

Jim Brown-10

Re: [KX3] Using a Sound Card for Mic (Multiple) Input(s)

In reply to this post by Joel Black-2

On Sat,5/28/2016 5:45 AM, Joel Black wrote:
>
> I currently have a Focusrite 2i2 I bought after my E-MU 0204 stopped working in OS X 10.11. It has two inputs and two outputs. Experimenting the other day, I tried using my MH3 mic on the input to the sound card with the sound card output going to the MIC IN on the KX3. It didn’t work. I then realized that the MH3 is a condenser mic and needs to be powered. The 2i2 has a “48 V phantom power” switch, but I am a little nervous of turning that on. I don’t want to let all the “magic smoke” out of my mic.

48V phantom power is exclusively for BALANCED mics wired from PRO use.
It does NOT work with the unbalanced electret mics we use with our ham
gear, and it would almost certainly fry them. The "bias" that we use for
unbalanced mics fulfills a similar function, but the two methods and
kinds of mics are incompatible.

> After all of that, I began remembering an issue I had with a Genesis G59 SDR I built several years ago - the delay in the route from audio in to the sound card, the sound card input being processed by the computer, the computer outputting that data to the transmitter. It was quite reminiscent of my days operating the HEO satellites. The delay is unnerving and I have never been able to compensate for it other than turning off MON. I’m supposing I’ll have the same delay if I incorporate a sound card for multiple inputs.
>
> Would I be better off just adding a mixer?

You haven't said what you want do do that you can't do with a mic and a
sound card, and what you expect a mixer to do. I strongly recommend that
you avoid a mixer. Far better to plug and unplug if you need to -- plug
in the mic for SSB, plug in a cable from computer audio for digital modes.

BTW -- the need to plug and unplug is one of the shortcomings of the KX3
(and KX2) as compared to K3/K3S. With the K3/K3S, you can leave
everything plugged in.

I do NOT recommend a mixer -- too many complications with hum, buzz, and
RFI and getting levels set right.

73, Jim K9YC
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