[Elecraft] K3 Hum on Audio...

Fri Jan 13 15:40:10 EST 2012

No one mentioned the firmware level but I am not on any beta version.  I am at MCU firmware level 4.39.

73, phil, K7PEH

On Jan 13, 2012, at 12:33 PM, NZ0T wrote:

> Phil, which firmware version are you using?  I was using the beta 4.47 and
> I developed audio problems the other night,  After I deleted 4.47 and went
> back to the latest production firmware all was fine.  Sorry if this has
> already been discussed - I just read this thread.
> 
> 73 Bill NZ0T
> 
> On Fri, Jan 13, 2012 at 1:32 PM, Phil Hystad-3 [via Elecraft] <
> ml-node+s365791n7185299h67 at n2.nabble.com> wrote:
> 
>> 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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