[Elecraft] [Elecraft_K3] RE: K3+microKeyer+MM: Realtek AC'97 feedback

[Eric Scace K3NA]

Thanks, Joe, Lyle and Tim (KT1D).  It was indeed the Playback Line In 
control being un-muted.  Now on to the next problem.

The tip to update the Router presets was especially valuable!

on 09 Mar 03 19:27 Joe Subich, W4TV said the following:
>> I suspect (but do not know) that it is the PC mixer configuration.
>>     
>
> I agree with Lyle ... the computer is almost certainly echoing Line 
> In to Line Out.  Right click on the task bar speaker Icon and 
> select "open Volume Control."  Select options | Properties | Playback 
> and the miser device for the soundcard to which microKEYER/K3 is 
> connected.  Look to see if Line In is one of the "Volume controls" 
> options ... enable it and click "OK."  Now, make sure the Line IN 
> level is all the way down and that channel is muted (note Line IN 
> may be identified by the color of its jack).  Update Router's presets 
> so the Line In is always muted on the playback side. 
>
> microKEYER does not have any ability to connect Line In to Line Out. 
>
> 73, 
>
>    ... Joe, W4TV 
>  
>
>
>
>
>   
>> -----Original Message-----
>> From: elecraft-bounces at mailman.qth.net 
>> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Lyle Johnson
>> Sent: Tuesday, March 03, 2009 6:26 PM
>> To: eric at k3na.org
>> Cc: Joe Subich W4TV; Elecraft mailing list; N1MM Logger; 
>> support at elecraft.com; Elecraft K3 mailing list
>> Subject: Re: [Elecraft] K3+microKeyer+MM: Realtek AC'97 feedback
>>
>>
>> Hello Eric!
>>
>>     
>>>    I'm seeking advice on a feedback problem.
>>>
>>>    Scenario:
>>> PC line out -> microKeyer -> K3 mic in (Note 5)
>>> PC line in <- K3 line out.  (Note 1)
>>>    Note 1:  microKeyer is bypassed so that stereo gets delivered to 
>>> the
>>> computer for archival recordings.
>>>    Note 2:  K3 CONFIG: LIN OUT can be either "nor 001" or "=phones" 
>>> without changing the problem.
>>>    Note 3:  To simplify and isolate the problem, MM is not running.
>>>    Note 4:  More details about the PC and K3 firmware listed below.
>>>    Note 5:  Can connect direct to K3 Line In (bypassing the 
>>>       
>> microKeyer), 
>>     
>>> changing MENU MIC SEL accordingly, without affecting the problem.
>>>
>>>    When I put the radio into TX (short the footswitch input on the
>>> microKeyer), and play an audio file out the PC, a feedback 
>>>       
>> loop exists.  
>>     
>>> The severity of the loop depends on the K3 MON setting: low setting 
>>> (<<10) means no echo chamber.
>>>
>>>    The only possibilities are the K3 is making the loop, or the 
>>> computer
>>> is making the loop.  I'm not sure how to isolate this.
>>>       
>> I suspect (but do not know) that it is the PC mixer configuration.
>>
>> If the K3 is outputting MON audio, then what appears at the 
>> K3 LINE IN 
>> will re-appeer at K3 LINE OUT with some delay and +/- gain. 
>> If the PC's 
>> mixer is active so that the PC LINE IN is mixed with whatever 
>> source you 
>> are playing back, then you'll probably get feedback.
>>
>> One way to tell is to remove the K3 and just loop the PC 
>> output back to 
>> its input.  You might want to listen on an amplified speaker using Y 
>> cable - or not, depending on how much you value your hearing :-)
>>
>> 73,
>>
>> Lyle KK7P 
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>
>
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