[Elecraft] K3 Hum on Audio...

Fri Jan 13 15:26:47 EST 2012

bob,

I am not sure if you understand my previous problems I was reporting.  The hum has nothing to do with the mic plugged into the K3 or not (obvious if the mic is not plugged in, there is no problems).  But, the hum comes with PTT transmit and not merely because the mic is plugged in.  

But, for some unusual reason, the hum is no longer there.  But I fear it is waiting out there, maybe in the greenbelt behind our house, to make a sneak attack when I least expect it.

73, phil

On Jan 13, 2012, at 12:09 PM, riese-k3djc at juno.com wrote:

> so you unplug the mike input to K3 the hum goes away
> when you plug into the K3 mike input the hum is there ?
> I would think you have a bad mike/cord/connecter
> 
> Bob K3DJC
> 
> On Fri, 13 Jan 2012 11:31:38 -0800 Phil Hystad <phystad at mac.com> writes:
>> Ron,
>> 
>> Well, I just had a quick SSB chat with Clyde (AA7WC) (pre Noon Time 
>> net on 40 meters) and asked specifically for audio report with 
>> possible hum.  His report was no hum, clear good sounding audio, 
>> with S7 signal.
>> 
>> So I am suspicious of my florescent lights in the garage although 
>> they are on right now with no hum.  I am thinking though that maybe 
>> there is something intermittent with those lights.  But, then again, 
>> the "something loose in the mic cord" maybe be the cause too.  But, 
>> I jiggled that cord and connection and so on quite vigorously before 
>> when I had the hum and it did not change the hum status.  Then, when 
>> the hum disappeared, I did those jiggle the cord and connector on 
>> the mic tests again and the hum DID NOT come back.
>> 
>> Wow, I can't believe I have spent the entire morning fooling around 
>> with this.  I even called into work and said that I was not coming 
>> in today just to work on this problem.  I don't really want to go 
>> outside anyway despite that the temperature has now risen to a 
>> toasty 36 degrees.
>> 
>> 73, phil, K7PEH
>> 
>> 
>> On Jan 13, 2012, at 11:23 AM, Ron D'Eau Claire wrote:
>> 
>>> Good luck Phil. That last part really suggests something loose in 
>> the mike
>>> cord as I suggested at first. 
>>> 
>>> Ron AC7AC
>>> 
>>> -----Original Message-----
>>> Ron,
>>> 
>>> OK, now it appears I was mistaken when I said that that the hum 
>> was in both
>>> mics.  I think I flubbed something up in my previous test due to 
>> the way
>>> that the macros are assigned to keys which led me to thinking that 
>> the hum
>>> occurred in both mics.   But, I learned something in this...
>>> 
>>> One, don't try to use one of your macro assigned keys (in my case 
>> M2 and M1)
>>> while in the menu because that merely reassigns the key to the new 
>> menu
>>> entry.  I made this mistake several times this morning.  But, when 
>> I
>>> discovered it and then reset my macro definitions, I rediscovered 
>> that the
>>> HUM occurs in the front panel MH2 hand held mic only.  I did this 
>> test
>>> several times to make sure I was not confusing things.
>>> 
>>> I discovered something else that I did not know before.  PTT is 
>> actuated by
>>> any of the methods of PTT.  So, when I thought I had the 
>> headphones CM500
>>> mic enabled I used my foot switch for push to talk and since that 
>> worked for
>>> some dumb reason I was thinking I had successfully switched from 
>> front panel
>>> to rear panel.  But, I had not.  I also discovered that I could 
>> use the hand
>>> mic (front panel) PTT switch even though my rear panel mic was 
>> being used.
>>> Now, after I discovered this, I realize that it is obvious but 
>> something
>>> that lead to my confusion.
>>> 
>>> So, the problem occurs on the FRONT PANEL mic only and not the 
>> rear panel.
>>> And, the problem occurs when the K3 is in TOTAL isolation from all 
>> AC
>>> sources except for possibly me.  I mean, I am holding the mic but 
>> then I
>>> don't think that is a cause of the hum because I tried it with a 
>> insulated
>>> hand and it still caused the hum on the front panel mic.
>>> 
>>> I doubt that this is caused by wall-outlet type AC because I have 
>> erased all
>>> AC for some of my tests.  And, besides, this problem seemed to 
>> occur ....
>>> 
>>> OK, while writing that last sentence something occurred to me.  
>> Another
>>> change I had made on Wednesday after I had my good audio reports 
>> on the MH2
>>> front panel mic was that I set the configuration for the band 
>> specific power
>>> levels to work with the KPA500.  So, I just now went to test the 
>> mic and
>>> change that setting around but the hum is gone.
>>> 
>>> I repeat, the hum is gone from the front panel mic.   I now can't 
>> test the
>>> band specific power menu setting because I have no problem.
>>> 
>>> But, I have a suspicion as to the cause now and I am going to do 
>> some other
>>> experiments.
>>> 
>>> 73, phil
>>> 
>> 
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