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K3 Distorted Sound while using AM

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Richard Jones - KJ5QY

K3 Distorted Sound while using AM

Hello,

I am having a problem when I go into AM, or AM sync. Example: I go to an AM Shortwave station. If I turn the AF gain past approximately 3/4 or farther the radio starts to "Stutter, Distort, and finally the audio disappears. I cannot make out what is coming out from my speaker. The audio is completely distorted or gone. I noticed I could rotate the Af gain (Counter Clockwise) and it would go back to less distortion. I did check the external speaker jack and also unplugged it only to find the same problem.

The AF knob feels like it was one of those "old potentiometers" that we are all aware of (Get scratchy after use and loose). From my understanding Elecraft used extremely fine pots with a very long life (They do have a bad wobble/looseness in them though).

Upon further investigation I found that if I rotated the RF gain control from the fully clockwise position (all the way open) to the full counter clockwise position (all the way closed) that when you almost get to the end of travel the radio audio goes completely dead. I have tried this multiples times and it is very repeatable.

After more investigation I found that if I rotated the "shift" (While in AM or Sync AM) control from its standard (Normal) value of 1.50 to 1.55 this horrible distortion would disappear? I am really confused as to what is going on here.

This happens while in the "Normal" AM mode as well as the "Sync" AM mode.

I have tried to explain this in away that I hope most people will understand my problem (I am not an EE).

Could others please let me know if it is my unit or a wider problem?

I am using 3.59 and the serial number is 283?. This unit was fully loaded and built by Elecraft.

Thanks,

Rick

Joe Planisky

Re: K3 Distorted Sound while using AM

Hi Rick,

Do you perhaps have AGC turned off and the AF LIM set to a value of
less than 30? The distortion and eventual cutting out of audio at
high levels you are describing sounds a lot like the intended AF
limiter action. If so, the solution is to either turn on AGC, or
increase the AF LIM setting closer to 30. I find an AF LIM setting of
28 allows as much dynamic range as I want while still protecting my
tender ears from various pops and static crashes.

The AF limiter is intended to protect your ears and speakers from
unexpectedly loud signals when AGC is turned off. It will prevent the
output from exceeding the preset value at the expense of distortion.

73
--
Joe KB8AP

On Dec 5, 2009, at 8:50 PM, Richard Jones - KJ5QY wrote:

>
> Hello,
>
> I am having a problem when I go into AM, or AM sync. Example: I go
> to an
> AM Shortwave station. If I turn the AF gain past approximately 3/4 or
> farther the radio starts to "Stutter, Distort, and finally the audio
> disappears. I cannot make out what is coming out from my speaker.
> The
> audio is completely distorted or gone. I noticed I could rotate the
> Af gain
> (Counter Clockwise) and it would go back to less distortion. I did
> check
> the external speaker jack and also unplugged it only to find the same
> problem.

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Richard Jones - KJ5QY

Re: K3 Distorted Sound while using AM

Hey Joe,

Thanks for the fast reply!

No, I do not have the AGC Off, nor have I changed any of the "settings" within the AGC (Menus). I should have stated that in my original post. Anyway, I am really stumped as what the problem is.

If you happen to have a K3 equipped as mine, could try to listen to an AM station with the "Volume" turned up, to see if you are receiving the distortion?

I should have been more specific, the radio is totally loaded. It does have the 8 Pole filters in both receivers. From my recollection I have the following filters: 250 Data & CW, 2.1 for SSB, 2.8 for SSB, and 6 for AM, and 13 for FM. I hope this makes it a litter clearer and not more confusing.

Thanks Joe,

Rick

Thanks,

Rick

Joe Planisky wrote

Hi Rick,

Do you perhaps have AGC turned off and the AF LIM set to a value of
less than 30? The distortion and eventual cutting out of audio at
high levels you are describing sounds a lot like the intended AF
limiter action. If so, the solution is to either turn on AGC, or
increase the AF LIM setting closer to 30. I find an AF LIM setting of
28 allows as much dynamic range as I want while still protecting my
tender ears from various pops and static crashes.

The AF limiter is intended to protect your ears and speakers from
unexpectedly loud signals when AGC is turned off. It will prevent the
output from exceeding the preset value at the expense of distortion.

73
--
Joe KB8AP

On Dec 5, 2009, at 8:50 PM, Richard Jones - KJ5QY wrote:

>
> Hello,
>
> I am having a problem when I go into AM, or AM sync. Example: I go
> to an
> AM Shortwave station. If I turn the AF gain past approximately 3/4 or
> farther the radio starts to "Stutter, Distort, and finally the audio
> disappears. I cannot make out what is coming out from my speaker.
> The
> audio is completely distorted or gone. I noticed I could rotate the
> Af gain
> (Counter Clockwise) and it would go back to less distortion. I did
> check
> the external speaker jack and also unplugged it only to find the same
> problem.

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Frank R. Oppedijk-2

Re: K3 Distorted Sound while using AM

Hi,

I've encountered the same once. It took me awhile to notice that the
distortion on AM was caused by the NB or NR being switched on. Might
this be your problem too?

73,

Frank PA4N

At 06:50 06/12/2009, Richard Jones - KJ5QY wrote:

>Hey Joe,
>
>Thanks for the fast reply!
>
>No, I do not have the AGC Off, nor have I changed any of the "settings"
>within the AGC (Menus). I should have stated that in my original post.
>Anyway, I am really stumped as what the problem is.
>
>If you happen to have a K3 equipped as mine, could try to listen to an AM
>station with the "Volume" turned up, to see if you are receiving the
>distortion?
>
>I should have been more specific, the radio is totally loaded. It does
>have the 8 Pole filters in both receivers. From my recollection I have the
>following filters: 250 Data & CW, 2.1 for SSB, 2.8 for SSB, and 6 for AM,
>and 13 for FM. I hope this makes it a litter clearer and not more
>confusing.

pd0psb

Re: K3 Distorted Sound while using AM

In reply to this post by Richard Jones - KJ5QY

Hi Richard,

How is your RX EQ set?

What you describe sounds like DAC stages maxing out on too much low (near DC) frequency content.
DC uses all bits and mutes DAC.

Turning down the lower RX EQ bands might help.

73'
Paul
PD0PSB

Richard Jones - KJ5QY wrote

Hello,

I am having a problem when I go into AM, or AM sync. Example: I go to an AM Shortwave station. If I turn the AF gain past approximately 3/4 or farther the radio starts to "Stutter, Distort, and finally the audio disappears. I cannot make out what is coming out from my speaker. The audio is completely distorted or gone. I noticed I could rotate the Af gain (Counter Clockwise) and it would go back to less distortion. I did check the external speaker jack and also unplugged it only to find the same problem.

The AF knob feels like it was one of those "old potentiometers" that we are all aware of (Get scratchy after use and loose). From my understanding Elecraft used extremely fine pots with a very long life (They do have a bad wobble/looseness in them though).

Upon further investigation I found that if I rotated the RF gain control from the fully clockwise position (all the way open) to the full counter clockwise position (all the way closed) that when you almost get to the end of travel the radio audio goes completely dead. I have tried this multiples times and it is very repeatable.

After more investigation I found that if I rotated the "shift" (While in AM or Sync AM) control from its standard (Normal) value of 1.50 to 1.55 this horrible distortion would disappear? I am really confused as to what is going on here.

This happens while in the "Normal" AM mode as well as the "Sync" AM mode.

I have tried to explain this in away that I hope most people will understand my problem (I am not an EE).

Could others please let me know if it is my unit or a wider problem?

I am using 3.59 and the serial number is 283?. This unit was fully loaded and built by Elecraft.

Thanks,

Rick

Bob Naumann W5OV

Re: K3 Distorted Sound while using AM

In reply to this post by Richard Jones - KJ5QY

Have you checked the wiring to your external speaker?

After the addition of the sync AM I have zero distortion on AM signals with
my K3 - I have the 6kHz filter for AM.

73,

Bob W5OV

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Richard Jones - KJ5QY
Sent: Saturday, December 05, 2009 11:50 PM
To: [hidden email]
Subject: Re: [Elecraft] K3 Distorted Sound while using AM

Hey Joe,

Thanks for the fast reply!

No, I do not have the AGC Off, nor have I changed any of the "settings"
within the AGC (Menus). I should have stated that in my original post.
Anyway, I am really stumped as what the problem is.

If you happen to have a K3 equipped as mine, could try to listen to an AM
station with the "Volume" turned up, to see if you are receiving the
distortion?

I should have been more specific, the radio is totally loaded. It does
have the 8 Pole filters in both receivers. From my recollection I have the
following filters: 250 Data & CW, 2.1 for SSB, 2.8 for SSB, and 6 for AM,
and 13 for FM. I hope this makes it a litter clearer and not more
confusing.

Thanks Joe,

Rick

Thanks,

Rick

Joe Planisky wrote:

>
> Hi Rick,
>
> Do you perhaps have AGC turned off and the AF LIM set to a value of
> less than 30? The distortion and eventual cutting out of audio at
> high levels you are describing sounds a lot like the intended AF
> limiter action. If so, the solution is to either turn on AGC, or
> increase the AF LIM setting closer to 30. I find an AF LIM setting of
> 28 allows as much dynamic range as I want while still protecting my
> tender ears from various pops and static crashes.
>
> The AF limiter is intended to protect your ears and speakers from
> unexpectedly loud signals when AGC is turned off. It will prevent the
> output from exceeding the preset value at the expense of distortion.
>
>
> 73
> --
> Joe KB8AP
>
>
>
> On Dec 5, 2009, at 8:50 PM, Richard Jones - KJ5QY wrote:
>
>>
>> Hello,
>>
>> I am having a problem when I go into AM, or AM sync. Example: I go
>> to an
>> AM Shortwave station. If I turn the AF gain past approximately 3/4 or
>> farther the radio starts to "Stutter, Distort, and finally the audio
>> disappears. I cannot make out what is coming out from my speaker.
>> The
>> audio is completely distorted or gone. I noticed I could rotate the
>> Af gain
>> (Counter Clockwise) and it would go back to less distortion. I did
>> check
>> the external speaker jack and also unplugged it only to find the same
>> problem.
>
> ______________________________________________________________
> 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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l
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Bob Naumann W5OV

Re: K3 Distorted Sound while using AM

In reply to this post by Richard Jones - KJ5QY

Sorry - I missed that you said you have this on the internal speaker also.

Very strange.

-----Original Message-----
From: Bob Naumann [mailto:[hidden email]]
Sent: Sunday, December 06, 2009 8:20 AM
To: 'Richard Jones - KJ5QY'; '[hidden email]'
Subject: RE: [Elecraft] K3 Distorted Sound while using AM

Have you checked the wiring to your external speaker?

After the addition of the sync AM I have zero distortion on AM signals with
my K3 - I have the 6kHz filter for AM.

73,

Bob W5OV

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Richard Jones - KJ5QY
Sent: Saturday, December 05, 2009 11:50 PM
To: [hidden email]
Subject: Re: [Elecraft] K3 Distorted Sound while using AM

Hey Joe,

Thanks for the fast reply!

No, I do not have the AGC Off, nor have I changed any of the "settings"
within the AGC (Menus). I should have stated that in my original post.
Anyway, I am really stumped as what the problem is.

If you happen to have a K3 equipped as mine, could try to listen to an AM
station with the "Volume" turned up, to see if you are receiving the
distortion?

I should have been more specific, the radio is totally loaded. It does
have the 8 Pole filters in both receivers. From my recollection I have the
following filters: 250 Data & CW, 2.1 for SSB, 2.8 for SSB, and 6 for AM,
and 13 for FM. I hope this makes it a litter clearer and not more
confusing.

Thanks Joe,

Rick

Thanks,

Rick

Joe Planisky wrote:

n7ws

Re: K3 Distorted Sound while using AM

In reply to this post by Richard Jones - KJ5QY

What firmware rev are you using?

--- On Sat, 12/5/09, Richard Jones - KJ5QY <[hidden email]> wrote:

From: Richard Jones - KJ5QY <[hidden email]>
Subject: [Elecraft] K3 Distorted Sound while using AM
To: [hidden email]
Date: Saturday, December 5, 2009, 9:50 PM

Hello,

I am having a problem when I go into AM, or AM sync. Example: I go to an
AM Shortwave station. If I turn the AF gain past approximately 3/4 or
farther the radio starts to "Stutter, Distort, and finally the audio
disappears. I cannot make out what is coming out from my speaker. The
audio is completely distorted or gone. I noticed I could rotate the Af gain
(Counter Clockwise) and it would go back to less distortion. I did check
the external speaker jack and also unplugged it only to find the same
problem.

The AF knob feels like it was one of those "old potentiometers" that we are
all aware of (Get scratchy after use and loose). From my understanding
Elecraft used extremely fine pots with a very long life (They do have a bad
wobble/looseness in them though).

Upon further investigation I found that if I rotated the RF gain control
from the fully clockwise position (all the way open) to the full counter
clockwise position (all the way closed) that when you almost get to the end
of travel the radio audio goes completely dead. I have tried this multiples
times and it is very repeatable.

After more investigation I found that if I rotated the "shift" (While in AM
or Sync AM) control from its standard (Normal) value of 1.50 to 1.55 this
horrible distortion would disappear? I am really confused as to what is
going on here.

This happens while in the "Normal" AM mode as well as the "Sync" AM mode.

I have tried to explain this in away that I hope most people will understand
my problem (I am not an EE).

Could others please let me know if it is my unit or a wider problem?

I am using 3.59 and the serial number is 283?. This unit was fully loaded
and built by Elecraft.

Thanks,

Rick
--
View this message in context: http://n2.nabble.com/K3-Distorted-Sound-while-using-AM-tp4120316p4120316.html
Sent from the Elecraft mailing list archive at Nabble.com.
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Matt Zilmer

Re: K3 Distorted Sound while using AM

In reply to this post by Richard Jones - KJ5QY

If you're using the 2.8 or 2.1 filters for AM mode reception, it would
probably sound distorted. The 2.8 works fine for listening to AM in
SSB mode though.

matt W6NIA
K3 #24

On Sat, 05 Dec 2009 21:50:28 -0800 (PST), you wrote:

>
>Hey Joe,
>
>Thanks for the fast reply!
>
>No, I do not have the AGC Off, nor have I changed any of the "settings"
>within the AGC (Menus). I should have stated that in my original post.
>Anyway, I am really stumped as what the problem is.
>
>If you happen to have a K3 equipped as mine, could try to listen to an AM
>station with the "Volume" turned up, to see if you are receiving the
>distortion?
>
>I should have been more specific, the radio is totally loaded. It does
>have the 8 Pole filters in both receivers. From my recollection I have the
>following filters: 250 Data & CW, 2.1 for SSB, 2.8 for SSB, and 6 for AM,
>and 13 for FM. I hope this makes it a litter clearer and not more
>confusing.
>
>Thanks Joe,
>
>Rick
>
>
>
>Thanks,
>
>Rick
>
>
>
>Joe Planisky wrote:
>>
>> Hi Rick,
>>
>> Do you perhaps have AGC turned off and the AF LIM set to a value of
>> less than 30? The distortion and eventual cutting out of audio at
>> high levels you are describing sounds a lot like the intended AF
>> limiter action. If so, the solution is to either turn on AGC, or
>> increase the AF LIM setting closer to 30. I find an AF LIM setting of
>> 28 allows as much dynamic range as I want while still protecting my
>> tender ears from various pops and static crashes.
>>
>> The AF limiter is intended to protect your ears and speakers from
>> unexpectedly loud signals when AGC is turned off. It will prevent the
>> output from exceeding the preset value at the expense of distortion.
>>
>>
>> 73
>> --
>> Joe KB8AP
>>
>>
>>
>> On Dec 5, 2009, at 8:50 PM, Richard Jones - KJ5QY wrote:
>>
>>>
>>> Hello,
>>>
>>> I am having a problem when I go into AM, or AM sync. Example: I go
>>> to an
>>> AM Shortwave station. If I turn the AF gain past approximately 3/4 or
>>> farther the radio starts to "Stutter, Distort, and finally the audio
>>> disappears. I cannot make out what is coming out from my speaker.
>>> The
>>> audio is completely distorted or gone. I noticed I could rotate the
>>> Af gain
>>> (Counter Clockwise) and it would go back to less distortion. I did
>>> check
>>> the external speaker jack and also unplugged it only to find the same
>>> problem.
>>
>> ______________________________________________________________
>> 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
>>
>>

drewko

Re: K3 Distorted Sound while using AM

In reply to this post by Richard Jones - KJ5QY

My audio will distort and cut out as you describe if it's a very
strong AM signal (nearly full scale on the s-meter) and the volume is
turned up to that extreme. But that is really loud. I usually have the
AF Gain set at 1/4 rotation or less, so don't really consider it a
problem here. I never under any circumstance have to go up as far as
3/4 on the AF Gain (unless the AGC is off and the RF Gain is way down,
in which case there is no distortion).

FWIW, you can set Config: AF GAIN to "HI" or "LO".

The feel of my AF & RF controls are smooth. They have a very small
side-to-side play but no bad wobble/looseness as you describe.

When I rotate the RF Gain full CCW it is very quiet, just a very faint
noise level can be heard with the AF Gain full CW. I consider it
normal operation.

73,
Drew
AF2Z

On Sat, 05 Dec 2009 20:50:25 -0800 (PST), you wrote:

>
>Hello,
>
>I am having a problem when I go into AM, or AM sync. Example: I go to an
>AM Shortwave station. If I turn the AF gain past approximately 3/4 or
>farther the radio starts to "Stutter, Distort, and finally the audio
>disappears. I cannot make out what is coming out from my speaker. The
>audio is completely distorted or gone. I noticed I could rotate the Af gain
>(Counter Clockwise) and it would go back to less distortion. I did check
>the external speaker jack and also unplugged it only to find the same
>problem.
>
>The AF knob feels like it was one of those "old potentiometers" that we are
>all aware of (Get scratchy after use and loose). From my understanding
>Elecraft used extremely fine pots with a very long life (They do have a bad
>wobble/looseness in them though).
>
>Upon further investigation I found that if I rotated the RF gain control
>from the fully clockwise position (all the way open) to the full counter
>clockwise position (all the way closed) that when you almost get to the end
>of travel the radio audio goes completely dead. I have tried this multiples
>times and it is very repeatable.
>
>After more investigation I found that if I rotated the "shift" (While in AM
>or Sync AM) control from its standard (Normal) value of 1.50 to 1.55 this
>horrible distortion would disappear? I am really confused as to what is
>going on here.
>
>This happens while in the "Normal" AM mode as well as the "Sync" AM mode.
>
>I have tried to explain this in away that I hope most people will understand
>my problem (I am not an EE).
>
>Could others please let me know if it is my unit or a wider problem?
>
>I am using 3.59 and the serial number is 283?. This unit was fully loaded
>and built by Elecraft.
>
>Thanks,
>
>Rick

Richard Jones - KJ5QY

Re: K3 Distorted Sound while using AM

In reply to this post by Bob Naumann W5OV

Hey Bob,

Sorry for not getting back to the board been a busy day. I have checked all the wiring. I have tried the 6hz AM filter. This really has me stumped. I will give Elecraft a call the first part of the week and see what we can come with.

Thanks,

Rick

Bob Naumann wrote

Have you checked the wiring to your external speaker?

After the addition of the sync AM I have zero distortion on AM signals with
my K3 - I have the 6kHz filter for AM.

73,

Bob W5OV

-----Original Message-----
From: elecraft-bounces@mailman.qth.net
[mailto:elecraft-bounces@mailman.qth.net] On Behalf Of Richard Jones - KJ5QY
Sent: Saturday, December 05, 2009 11:50 PM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3 Distorted Sound while using AM

Hey Joe,

Thanks for the fast reply!

No, I do not have the AGC Off, nor have I changed any of the "settings"
within the AGC (Menus). I should have stated that in my original post.
Anyway, I am really stumped as what the problem is.

If you happen to have a K3 equipped as mine, could try to listen to an AM
station with the "Volume" turned up, to see if you are receiving the
distortion?

I should have been more specific, the radio is totally loaded. It does
have the 8 Pole filters in both receivers. From my recollection I have the
following filters: 250 Data & CW, 2.1 for SSB, 2.8 for SSB, and 6 for AM,
and 13 for FM. I hope this makes it a litter clearer and not more
confusing.

Thanks Joe,

Rick

Thanks,

Rick

Joe Planisky wrote:
>
> Hi Rick,
>
> Do you perhaps have AGC turned off and the AF LIM set to a value of
> less than 30? The distortion and eventual cutting out of audio at
> high levels you are describing sounds a lot like the intended AF
> limiter action. If so, the solution is to either turn on AGC, or
> increase the AF LIM setting closer to 30. I find an AF LIM setting of
> 28 allows as much dynamic range as I want while still protecting my
> tender ears from various pops and static crashes.
>
> The AF limiter is intended to protect your ears and speakers from
> unexpectedly loud signals when AGC is turned off. It will prevent the
> output from exceeding the preset value at the expense of distortion.
>
>
> 73
> --
> Joe KB8AP
>
>
>
> On Dec 5, 2009, at 8:50 PM, Richard Jones - KJ5QY wrote:
>
>>
>> Hello,
>>
>> I am having a problem when I go into AM, or AM sync. Example: I go
>> to an
>> AM Shortwave station. If I turn the AF gain past approximately 3/4 or
>> farther the radio starts to "Stutter, Distort, and finally the audio
>> disappears. I cannot make out what is coming out from my speaker.
>> The
>> audio is completely distorted or gone. I noticed I could rotate the
>> Af gain
>> (Counter Clockwise) and it would go back to less distortion. I did
>> check
>> the external speaker jack and also unplugged it only to find the same
>> problem.
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>

--
View this message in context:
http://n2.nabble.com/K3-Distorted-Sound-while-using-AM-tp4120316p4120453.htm
l
Sent from the Elecraft mailing list archive at Nabble.com.
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Richard Jones - KJ5QY

Re: K3 Distorted Sound while using AM

In reply to this post by Richard Jones - KJ5QY

I think I found at least one of the problems.

If you go into the "RX EQ" (by clicking the "MENU" button, then turning the knob until you see the "RX EQ 1"). Next, turn the lowest base control (Number 1) up from the "0" EQ position until you here the distortion on AM. It will not take much. On my rig, just taking it a few levels (Db) above the "reference" the distortion on AM is there in a vengeance.

The following is the most important as I have found: If you have/get the distortion and you raise the "Shift Control" (While in AM or AM Sync) from "*150" to "155", the distortion completely goes away!!! I am not sure what is going on here.

I hope this, and the posts above will give some additional information on what I am experiencing, and hopefully an answer.

Thanks,

Rick

Richard Jones - KJ5QY wrote

Hello,

I am having a problem when I go into AM, or AM sync. Example: I go to an AM Shortwave station. If I turn the AF gain past approximately 3/4 or farther the radio starts to "Stutter, Distort, and finally the audio disappears. I cannot make out what is coming out from my speaker. The audio is completely distorted or gone. I noticed I could rotate the Af gain (Counter Clockwise) and it would go back to less distortion. I did check the external speaker jack and also unplugged it only to find the same problem.

The AF knob feels like it was one of those "old potentiometers" that we are all aware of (Get scratchy after use and loose). From my understanding Elecraft used extremely fine pots with a very long life (They do have a bad wobble/looseness in them though).

Upon further investigation I found that if I rotated the RF gain control from the fully clockwise position (all the way open) to the full counter clockwise position (all the way closed) that when you almost get to the end of travel the radio audio goes completely dead. I have tried this multiples times and it is very repeatable.

After more investigation I found that if I rotated the "shift" (While in AM or Sync AM) control from its standard (Normal) value of 1.50 to 1.55 this horrible distortion would disappear? I am really confused as to what is going on here.

This happens while in the "Normal" AM mode as well as the "Sync" AM mode.

I have tried to explain this in away that I hope most people will understand my problem (I am not an EE).

Could others please let me know if it is my unit or a wider problem?

I am using 3.59 and the serial number is 283?. This unit was fully loaded and built by Elecraft.

Thanks,

Rick

pd0psb

Re: K3 Distorted Sound while using AM

Thanks Richard,

To me that's an indication the DAC stages are indeed maxing out on LF (near DC) content.
Either reducing the low EQ or shifting the passband up alleviates this.

Some sort of DC blocking between DSP and DAC could help.
(also for the PB shift "clicking" effects)

73'
Paul
PD0PSB

Richard Jones - KJ5QY wrote

I think I found at least one of the problems.

If you go into the "RX EQ" (by clicking the "MENU" button, then turning the knob until you see the "RX EQ 1"). Next, turn the lowest base control (Number 1) up from the "0" EQ position until you here the distortion on AM. It will not take much. On my rig, just taking it a few levels (Db) above the "reference" the distortion on AM is there in a vengeance.

The following is the most important as I have found: If you have/get the distortion and you raise the "Shift Control" (While in AM or AM Sync) from "*150" to "155", the distortion completely goes away!!! I am not sure what is going on here.

I hope this, and the posts above will give some additional information on what I am experiencing, and hopefully an answer.

Thanks,

Rick

Richard Jones - KJ5QY wrote

Hello,

I am having a problem when I go into AM, or AM sync. Example: I go to an AM Shortwave station. If I turn the AF gain past approximately 3/4 or farther the radio starts to "Stutter, Distort, and finally the audio disappears. I cannot make out what is coming out from my speaker. The audio is completely distorted or gone. I noticed I could rotate the Af gain (Counter Clockwise) and it would go back to less distortion. I did check the external speaker jack and also unplugged it only to find the same problem.

The AF knob feels like it was one of those "old potentiometers" that we are all aware of (Get scratchy after use and loose). From my understanding Elecraft used extremely fine pots with a very long life (They do have a bad wobble/looseness in them though).

Upon further investigation I found that if I rotated the RF gain control from the fully clockwise position (all the way open) to the full counter clockwise position (all the way closed) that when you almost get to the end of travel the radio audio goes completely dead. I have tried this multiples times and it is very repeatable.

After more investigation I found that if I rotated the "shift" (While in AM or Sync AM) control from its standard (Normal) value of 1.50 to 1.55 this horrible distortion would disappear? I am really confused as to what is going on here.

This happens while in the "Normal" AM mode as well as the "Sync" AM mode.

I have tried to explain this in away that I hope most people will understand my problem (I am not an EE).

Could others please let me know if it is my unit or a wider problem?

I am using 3.59 and the serial number is 283?. This unit was fully loaded and built by Elecraft.

Thanks,

Rick

Guy, K2AV

Re: K3 Distorted Sound while using AM

In reply to this post by Richard Jones - KJ5QY

I have utterly clear AM reception. And am so far unable to reproduce
your symptoms.

I'm not sure what firmware you are using but with last couple beta
versions it is possible to drive the DAC circuits into overrange
"blast" protection muting.

It is possible to accentuate the lows on AM to the point that it
overdrives the range of the DAC, regardless of what the AGC is doing.
When this happens the DSP programs goes into mute mode to keep from
creating garbage numbers in the program that blow your ears off. This
feature has been very strongly requested by K3 owners (not a
"mistake") and is decidedly on purpose. (See the very long threads
related to "blast".)

Set all of your equalizer settings to flat. Make sure that you are not
receiving the carrier at the edge of your passband, as full carrier is
needed to demodulate without distortion on regular AM signals (not a
K3 requirement, just physics). Even with synchronous AM, the carrier
must still be in the passband to participate in the continuous
sychronizing process.

On synchronous AM the SHIFT control only displays USB or LSB to let
you know which sideband is being used plus the carrier for synchronous
demodulation.

On non-synchronous, the SHIFT control is fairly useless as all it does
is shift the passband at a minor rate versus the tuning knob. On AM
the sideband demodulation is provided by the carrier, so the SSB shift
effect does not work. If it is moving the audio into distortion then
the AM carrier is being moved out of the passband and its level being
reduced below that of the sidebands. Standard AM demodulation
requires that the carrier be a greater level than the sidebands.

Since the carrier has a fixed relationship to its sidebands, the
typical SSB shift effects for low or high audio do not apply for
standard AM demodulation, only if demodulating it as SSB. In order to
use shift to reduce lows in standard AM demodulation you would first
need to tune through one sideband's low audio, leaving the low on the
other side of carrier still providing lows. Then through the carrier
and only then through the other lows. However since you tuned out the
carrier, the demodulation will go into distortion before you can slice
the lows on the other side of carrier.

The only audio range you can tune out in standard AM demodulation
without distortion is highs, and that requires reducing bandwidth with
the carrier in the center of the passband.

On one level your issues sound like trying to demodulate AM using a
2.7 or 2.8 SSB filter, which really sounds pretty awful. Just for
jollies make sure with the current K3 utility that you have the proper
filter chosen in the filter configuration menu, and that there is not
a mistake in the slot being used for your filters.

If you do not have a 6.0 or 13 kHz filter, the only good sounding
demodulation of an AM signal is SSB on one or the other sideband.
This is surprisingly good sounding, and I use it for listening to BC
that is down in the noise (e.g afternoon Yankee games on WCBS 880). I
actually use as narrow as 1.8 kHz SSB with the shift and width
adjusted for best voice versus noise. The NR usually has a setting
which improves it further.

This is the most attention given to AM by hams that I've seen in 40
years. I've gone back to listening to AM broadcasts on my K3 (BC and
HF) while I'm workbenching. There is some high grade stuff out there
to be found, and for me the K3's rendition is superior. At my age I
don't hear the 60 dB down 8 kHz buzzy artifact stuff that some people
complain about. IMHO that's something that needs to be fixed in the
analog by reducing the analog bandwidth above 4 or 5 kHz. Or fixed by
providing an actual hi-fi demod/audio board as an option for those who
want such.

73, Guy.

On Mon, Dec 7, 2009 at 1:34 AM, Richard Jones - KJ5QY <[hidden email]> wrote:

>
> I think I found at least one of the problems.
>
> If you go into the "RX EQ" (by clicking the "MENU" button, then turning the
> knob until you see the "RX EQ 1"). Next, turn the lowest base control
> (Number 1) up from the "0" EQ position until you here the distortion on AM.
> It will not take much. On my rig, just taking it a few levels (Db) above
> the "reference" the distortion on AM is there in a vengeance.
>
> The following is the most important as I have found: If you have/get the
> distortion and you raise the "Shift Control" (While in AM or AM Sync) from
> "*150" to "155", the distortion completely goes away!!! I am not sure what
> is going on here.
>
> I hope this, and the posts above will give some additional information on
> what I am experiencing, and hopefully an answer.
>
> Thanks,
>
> Rick
>
>
>
> Richard Jones - KJ5QY wrote:
>>
>> Hello,
>>
>> I am having a problem when I go into AM, or AM sync. Example: I go to an
>> AM Shortwave station. If I turn the AF gain past approximately 3/4 or
>> farther the radio starts to "Stutter, Distort, and finally the audio
>> disappears. I cannot make out what is coming out from my speaker. The
>> audio is completely distorted or gone. I noticed I could rotate the Af
>> gain (Counter Clockwise) and it would go back to less distortion. I did
>> check the external speaker jack and also unplugged it only to find the
>> same problem.
>>
>> The AF knob feels like it was one of those "old potentiometers" that we
>> are all aware of (Get scratchy after use and loose). From my
>> understanding Elecraft used extremely fine pots with a very long life
>> (They do have a bad wobble/looseness in them though).
>>
>> Upon further investigation I found that if I rotated the RF gain control
>> from the fully clockwise position (all the way open) to the full counter
>> clockwise position (all the way closed) that when you almost get to the
>> end of travel the radio audio goes completely dead. I have tried this
>> multiples times and it is very repeatable.
>>
>> After more investigation I found that if I rotated the "shift" (While in
>> AM or Sync AM) control from its standard (Normal) value of 1.50 to 1.55
>> this horrible distortion would disappear? I am really confused as to what
>> is going on here.
>>
>> This happens while in the "Normal" AM mode as well as the "Sync" AM mode.
>>
>> I have tried to explain this in away that I hope most people will
>> understand my problem (I am not an EE).
>>
>> Could others please let me know if it is my unit or a wider problem?
>>
>> I am using 3.59 and the serial number is 283?. This unit was fully loaded
>> and built by Elecraft.
>>
>> Thanks,
>>
>> Rick
>>
>
> --
> View this message in context: http://n2.nabble.com/K3-Distorted-Sound-while-using-AM-tp4120316p4124621.html
> Sent from the [K3] mailing list archive at Nabble.com.
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
>

Bill VanAlstyne W5WVO

Re: K3 Distorted Sound while using AM

Even if you do have a wide roofing filter, this method is
oftentimes superior when listening to weak-signal HF broadcast
signals at 5 kHz (or less) channel spacing. Typically, one
sideband will present significantly less interference than the
other, providing intelligible copy that is unattainable listening
to full-bandwidth double-sideband AM in the usual fashion.

Bill W5WVO

----- Original Message -----
From: "Guy Olinger K2AV" <[hidden email]>
To: "Richard Jones - KJ5QY" <[hidden email]>
Cc: <[hidden email]>
Sent: Monday, December 07, 2009 10:42 AM
Subject: Re: [Elecraft] [K3] K3 Distorted Sound while using AM

> ...If you do not have a 6.0 or 13 kHz filter, the only
> good sounding demodulation of an AM signal is SSB
> on one or the other sideband. This is surprisingly
> good sounding, and I use it for listening to BC that
> is down in the noise ... I actually use as narrow as
> 1.8 kHz SSB with the shift and width adjusted for
> best voice versus noise...

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Tom-5

Re: K3 Distorted Sound while using AM, now, speaking of AM..

Speaking of AM. There is a group that runs a weekly AM net on 50.400
here in West Michigan. Almost all are using vintage tube gear, which is
OK, but I would like to check in with the K3. Right now, all I have is
the 2.7 KHz SSB filter, and I can listen to them, but these radios are
many times 2-4 kHz off frequency, so I have to tune around. Time to get
a filter so I can transmit.

So would I do better in listening and transmitting with the 6 or the
13 Khz filter? I won't have the low band interference like I would on
75. And doesn't the K3 limit the audio response on TX to around 3 Khz?

Anyone else spend any amount of time on 6 AM?

73 de tom K8TB

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Steve Ellington

Re: K3 Distorted Sound while using AM, now, speaking of AM..

Personally I would feel more at home with this bunch by just buying an old
6m tube rig like the Clegg 99er or Gonset Communicator. One could probably
obtained for the same or less cost of a K3 filter.
Steve
N4LQ
[hidden email]
----- Original Message -----
From: "K8TB" <[hidden email]>
To: "'Elecraft Reflector'" <[hidden email]>
Sent: Monday, December 07, 2009 8:00 PM
Subject: Re: [Elecraft] [K3] K3 Distorted Sound while using AM, now,
speaking of AM..

> Speaking of AM. There is a group that runs a weekly AM net on 50.400
> here in West Michigan. Almost all are using vintage tube gear, which is
> OK, but I would like to check in with the K3. Right now, all I have is
> the 2.7 KHz SSB filter, and I can listen to them, but these radios are
> many times 2-4 kHz off frequency, so I have to tune around. Time to get
> a filter so I can transmit.
>
> So would I do better in listening and transmitting with the 6 or the
> 13 Khz filter? I won't have the low band interference like I would on
> 75. And doesn't the K3 limit the audio response on TX to around 3 Khz?
>
> Anyone else spend any amount of time on 6 AM?
>
> 73 de tom K8TB
>
> ______________________________________________________________
> 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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Richard Jones - KJ5QY

Re: K3 Distorted Sound while using AM

In reply to this post by Richard Jones - KJ5QY

Thanks to all that have replied in trying to help me!

There was just a new download posted from Elecraft K3# for (3.66). This seems to have taken care of all the problem I was having. The radio is now sounding much like a "Superb SW" receiver in its
sound. I will be testing it on AM as well as the "New" AM mode, synchronous detection!

For anyone who has not tried it, it is the "cats meow". Listening to "Foreign Broadcasters" is something to behold, if you have not had the pleasure please cheek it out! It is especially interesting when (the signals have) multiple hops or maybe going over the polls to your receive antenna!

I am very much aware that there are "many" SW (Short Wave) Listeners (and a few of us hams) using the Elecraft K3, please enjoy!

Thanks again for all who have answered my original question!!!!

Regards,

Rick

Richard Jones - KJ5QY wrote

Hello,

I am having a problem when I go into AM, or AM sync. Example: I go to an AM Shortwave station. If I turn the AF gain past approximately 3/4 or farther the radio starts to "Stutter, Distort, and finally the audio disappears. I cannot make out what is coming out from my speaker. The audio is completely distorted or gone. I noticed I could rotate the Af gain (Counter Clockwise) and it would go back to less distortion. I did check the external speaker jack and also unplugged it only to find the same problem.

The AF knob feels like it was one of those "old potentiometers" that we are all aware of (Get scratchy after use and loose). From my understanding Elecraft used extremely fine pots with a very long life (They do have a bad wobble/looseness in them though).

Upon further investigation I found that if I rotated the RF gain control from the fully clockwise position (all the way open) to the full counter clockwise position (all the way closed) that when you almost get to the end of travel the radio audio goes completely dead. I have tried this multiples times and it is very repeatable.

After more investigation I found that if I rotated the "shift" (While in AM or Sync AM) control from its standard (Normal) value of 1.50 to 1.55 this horrible distortion would disappear? I am really confused as to what is going on here.

This happens while in the "Normal" AM mode as well as the "Sync" AM mode.

I have tried to explain this in away that I hope most people will understand my problem (I am not an EE).

Could others please let me know if it is my unit or a wider problem?

I am using 3.59 and the serial number is 283?. This unit was fully loaded and built by Elecraft.

Thanks,

Rick