Re: [Elecraft] K2 audio output question

[Chuck Chandler]

Thanks for the tip!

73 de Chuck, WS1L

chandler...@gmail.com


On Mon, Jan 4, 2021 at 12:35 PM Geert Jan de Groot  wrote:

> On 04/01/2021 04:13, elecraft-requ...@mailman.qth.net wrote:
> > Is there a way to have both headphones and external speaker active at the
> > same time?  I'm thinking of being able to have audio for visitors while
> > still using headphones to copy.
>
> In addition to Don's response, you may want to look at this:
> https://www.w8fgu.com/pics/k2faob/w3fpr_K2%20audio%20Fix.pdf
> http://www.w3fpr.com/download_files/FP-CB%20mounting%20photos.pdf
>
> I have done this, using a piece of perfboard.
> To avoid shorts, in my case the PCB is in a piece of heat shrink tube.
>
> If you want a kit, check out https://www.w8fgu.com/k2_fixedaudio.html
>
> Instead of perfboarding it, I should have bought a kit from Dave, but
> sending a parcel by mail to PA0 would need me to mortgage my house, not
> to mention a lot of patience (another PCB ordered recently was stuck for
> *nine months* in Chicago).
>
> The advantage is that the 2nd output is fixed audio volume, so you can
> adjust the speaker audio and the headset audio separately.
>
> In my case (connecting multiple headsets on the speaker output) this
> approach has another advantage: I added audio sidetone to my K2 so that
> the people using headphones can hear eachother speak, yet the
> fixed-audio output doesn't have this, so there is no feedback from the
> speaker.
>
> When you use a speaker, make sure you use one that works well for SSB
> audio. For visitors, I would consider making some headsets available
> instead. SSB-via-speaker is more difficult to decode, SSB-via-speaker
> for people without SSB ears will just result in "there was a guy playing
> radio noise" at the exhibition.
>
> 73,
>
> Geert Jan PE1HZG
>
>
>
>
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Re: [Elecraft] K2 audio output question

[Geert Jan de Groot]

On 04/01/2021 04:13, elecraft-requ...@mailman.qth.net wrote:

Is there a way to have both headphones and external speaker active at the
same time?  I'm thinking of being able to have audio for visitors while
still using headphones to copy.


In addition to Don's response, you may want to look at this:
https://www.w8fgu.com/pics/k2faob/w3fpr_K2%20audio%20Fix.pdf
http://www.w3fpr.com/download_files/FP-CB%20mounting%20photos.pdf

I have done this, using a piece of perfboard.
To avoid shorts, in my case the PCB is in a piece of heat shrink tube.

If you want a kit, check out https://www.w8fgu.com/k2_fixedaudio.html

Instead of perfboarding it, I should have bought a kit from Dave, but 
sending a parcel by mail to PA0 would need me to mortgage my house, not 
to mention a lot of patience (another PCB ordered recently was stuck for 
*nine months* in Chicago).


The advantage is that the 2nd output is fixed audio volume, so you can 
adjust the speaker audio and the headset audio separately.


In my case (connecting multiple headsets on the speaker output) this 
approach has another advantage: I added audio sidetone to my K2 so that 
the people using headphones can hear eachother speak, yet the 
fixed-audio output doesn't have this, so there is no feedback from the 
speaker.


When you use a speaker, make sure you use one that works well for SSB 
audio. For visitors, I would consider making some headsets available 
instead. SSB-via-speaker is more difficult to decode, SSB-via-speaker 
for people without SSB ears will just result in "there was a guy playing 
radio noise" at the exhibition.


73,

Geert Jan PE1HZG



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Re: [Elecraft] K2 audio output question

[Walter Underwood]

My KX3 only has a Phones output and that won’t drive speakers well, so I use an 
off-the-shelf headphone splitter and a cheap audio amp that runs off 12 V. The 
details are here.

https://observer.wunderwood.org/2017/03/04/speakers-for-my-elecraft-kx3/ 


It looks like that particular audio amp isn’t available now, but there are 
plenty of similar cheap ones on Amazon.

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Jan 3, 2021, at 10:26 AM, Don Wilhelm  wrote:
> 
> Chuck,
> 
> Yes, you can do that by soldering a jumper across the switch at the rear of 
> the headphone jack.
> If you prefer not to add the jumper, plug stereo computer speakers into the 
> headphone jack and plug your headphones into the headphone jack on the 
> speaker.
> Try different computer speakers, some mute the speakers when headphones are 
> plugged in, others do not.
> 
> 73,
> Don W3FPR
> 
> On 1/3/2021 12:58 PM, Chuck Chandler wrote:
>> I've recently begun volunteering aboard the museum ship USS Slater, where
>> they have a K2 in Radio Central.  I've looked through the manual, but might
>> have overlooked this.
>> Is there a way to have both headphones and external speaker active at the
>> same time?  I'm thinking of being able to have audio for visitors while
>> still using headphones to copy.
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> Message delivered to wun...@wunderwood.org 

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Re: [Elecraft] K2 audio output question

[Don Wilhelm]

Chuck,

Yes, you can do that by soldering a jumper across the switch at the rear 
of the headphone jack.
If you prefer not to add the jumper, plug stereo computer speakers into 
the headphone jack and plug your headphones into the headphone jack on 
the speaker.
Try different computer speakers, some mute the speakers when headphones 
are plugged in, others do not.


73,
Don W3FPR

On 1/3/2021 12:58 PM, Chuck Chandler wrote:

I've recently begun volunteering aboard the museum ship USS Slater, where
they have a K2 in Radio Central.  I've looked through the manual, but might
have overlooked this.

Is there a way to have both headphones and external speaker active at the
same time?  I'm thinking of being able to have audio for visitors while
still using headphones to copy.


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Re: [Elecraft] K2 audio output low after upgrades

[Iain Kelly M0PCB]

Hi Don,

Thanks for the pointers. We've just spent half an hour working through 
all of the steps that Chloe had gone through to install the extras and 
we spotted a few joints that needed touching up from the previous 
owner's build. Just tested the radio and we're back to full audio 
output. Not 100% sure which of the steps fixed it, but we're glad it's 
sorted.


Thanks for your advice, Chloe is just finalising the re-assembly after 
testing so she'll be on the air again in no time.


73, Iain M0PCB

On 31/08/2013 19:46, Don Wilhelm wrote:

Iain,

I suspect it is not really an audio problem, but a problem somewhere 
in the receiver front end or IF or product detector.  If the S-meter 
is less lively than before, the problem is prior to the Product 
Detector, but if the S-meter has the usual response, look at the 
product detector and audio amp connections.  Was the KAF2 plugged into 
the headers one pin too high - that leaves only half of the audio path 
operative.


I would suspect the K60XV above all the other options.  Pull it out of 
the socket and jumper J13 between pins 3 and 5 with a short wire.  If 
the receive comes alive (it is not expected to work on 40 meters), 
then the K60XV is the problem spot.
It is easy to remove the KAT2 for a test, just pull the cables out and 
connect the antenna to the base K2..
If the other options were removed, make certain they are plugged in 
correctly and not one pin off.
You can bypass the KSB2 for receive (not transmit) with a wire jumper 
plugged between pins 1 and 3 of J9 and J10.
The K160RX can be bypassed by putting a wire jumper between pins 1 and 
7 of J14.


If all those things check out OK, then look for something that was 
inadvertently moved during the addition of the new options.


73,
Don W3FPR

On 8/31/2013 11:34 AM, Iain Kelly M0PCB wrote:

Greetings list,

I've been assisting my partner Chloe M0GEJ with some upgrades to her 
K2 (s/n 5484) and we've come a bit unstuck.


It's  a base K2 with SSB, 160m and the KAF2. She has added the 
internal ATU and the 60M module. She also had to replace a faulty 
headphone jack on the front panel as it had gone u/s. When 
re-assembled we noticed the audio output level is significantly down 
on what it was before.


The CW side-tone level is unaffected. Both the speaker and phone jack 
are affected. The audio level at maximum volume setting is just below 
normal levels required in headphonesand not very loud for internal 
speaker use.


What we have tried:

 - Full receive and transmit alignment: signals are received well and 
showing good strength on the s-meter, both off-air and from my signal 
generator.

 - RF Gain set to Max
 - Checked RANT selection
 - Checked R1 (AGC Threshold setting)
 - Measured the 5V and 8V lines
 - Replaced U9 (LM380N-08) on the main board in case the old damaged 
headphone jack had caused damage.






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Re: [Elecraft] K2 audio output low after upgrades

[Don Wilhelm]

Iain,

I suspect it is not really an audio problem, but a problem somewhere in 
the receiver front end or IF or product detector.  If the S-meter is 
less lively than before, the problem is prior to the Product Detector, 
but if the S-meter has the usual response, look at the product detector 
and audio amp connections.  Was the KAF2 plugged into the headers one 
pin too high - that leaves only half of the audio path operative.


I would suspect the K60XV above all the other options.  Pull it out of 
the socket and jumper J13 between pins 3 and 5 with a short wire.  If 
the receive comes alive (it is not expected to work on 40 meters), then 
the K60XV is the problem spot.
It is easy to remove the KAT2 for a test, just pull the cables out and 
connect the antenna to the base K2..
If the other options were removed, make certain they are plugged in 
correctly and not one pin off.
You can bypass the KSB2 for receive (not transmit) with a wire jumper 
plugged between pins 1 and 3 of J9 and J10.
The K160RX can be bypassed by putting a wire jumper between pins 1 and 7 
of J14.


If all those things check out OK, then look for something that was 
inadvertently moved during the addition of the new options.


73,
Don W3FPR

On 8/31/2013 11:34 AM, Iain Kelly M0PCB wrote:

Greetings list,

I've been assisting my partner Chloe M0GEJ with some upgrades to her 
K2 (s/n 5484) and we've come a bit unstuck.


It's  a base K2 with SSB, 160m and the KAF2. She has added the 
internal ATU and the 60M module. She also had to replace a faulty 
headphone jack on the front panel as it had gone u/s. When 
re-assembled we noticed the audio output level is significantly down 
on what it was before.


The CW side-tone level is unaffected. Both the speaker and phone jack 
are affected. The audio level at maximum volume setting is just below 
normal levels required in headphonesand not very loud for internal 
speaker use.


What we have tried:

 - Full receive and transmit alignment: signals are received well and 
showing good strength on the s-meter, both off-air and from my signal 
generator.

 - RF Gain set to Max
 - Checked RANT selection
 - Checked R1 (AGC Threshold setting)
 - Measured the 5V and 8V lines
 - Replaced U9 (LM380N-08) on the main board in case the old damaged 
headphone jack had caused damage.




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Re: [Elecraft] K2 Audio Output Mod

[Ariel Jacala]

The last sentence should have stated does not assure me ..

Ariel NY4G

Sent from my iPad

On Oct 11, 2012, at 10:31 AM, Ariel Jacala n...@hotmail.com wrote:

 Using the N0SS printed circuit board I am using the plans Don Wilhelm 
 published in August 2009.  Are there resistance checks I can do to assure 
 myself that I did an acceptable solder job?  My eyes and manual dexterity 
 have deteriorated to a point that a 10x visual examination by myself assures 
 me that things will work as planned.
 
 Ariel NY4G
 
 Sent from my iPad
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Re: [Elecraft] K2 Audio Output Mod

[Don Wilhelm]

Ariel,

There are very few places to check resistance.  You should find a high 
resistance at all pins of the LM386 (except perhaps pin 6 which is the 
voltage rail and pin 4 which is ground.

Note that all other pins have a capacitor and that will stop DC 
continuity - therefore giving a high resistance reading.
The best way to check it is to apply a sine wave (tune to a steady 
carrier) to the input and look with a 'scope at pins 2, 3 and 5.

73,
Don W3FPR

On 10/11/2012 10:30 AM, Ariel Jacala wrote:
 Using the N0SS printed circuit board I am using the plans Don Wilhelm 
 published in August 2009.  Are there resistance checks I can do to assure 
 myself that I did an acceptable solder job?  My eyes and manual dexterity 
 have deteriorated to a point that a 10x visual examination by myself assures 
 me that things will work as planned.

 Ariel NY4G



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RE: [Elecraft] K2 Audio Output

[Chuck Gehring]

Steve Kercel
AA4AK wrote:
Does the K2 produce sufficient audio power to drive a set of Bose
Quiet Comfort 2 noise cancelling headphones?

Has anyone on the list tried Bose Quiet Comfort 2 noise cancelling
headphones with a K2?

Steve,
I use the Bose QuietComfort 2 noise cancelling headphones all the time with
my K2.  They work great.

73 K2CG
Chuck Gehring
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