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K3 headphones

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rfenabled

K3 headphones

To provide best sensitivity, clarity and faithful reproduction during contesting, what would be the preferred specification that is NOT brand specific as many headphones are not available where I live.

Having looked around a bit I see varying types ranging from 4 to 600 Ohms and I would appreciate it very much if somebody could steer me in the right direction.

I would prefer to use the front Jack and I will be using SSB and working weak signal stations.

All advice welcome from the group.

Gary
Sent via BlackBerry® from Telstra
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Steve Ellington

Re: K3 headphones

Gary:
Did you search the archives? This topic has been run into the ground many
times.
Most any headphone can faithfully reproduce voice. If I were contesting, I
would use a "Headset" instead of headphones. Headsets have microphones. This
greatly limits your choices but as you requested, I can NOT be brand
specific due to your secret location.
For contesting you should be concerned with comfort and since we all have
different ideas about that, you'll have to try some on yourself. I prefer an
"over the ear" cup for long periods. Can't mention brand though! As for
Ohms; Mine are 32 ohms. I have an 8 ohm set and it is much louder plus it
sounds better but squishes my ear lobes so I can't wear them for more than a
few minutes. Can't mention brand.

BTW: The maker of the K3 sells a nice headset. Sorry, can't mention brand.

Steve N4LQ
----- Original Message -----
From: <[hidden email]>
To: "Elecraft" <[hidden email]>
Sent: Monday, June 22, 2009 10:57 AM
Subject: [Elecraft] K3 headphones

To provide best sensitivity, clarity and faithful reproduction during
contesting, what would be the preferred specification that is NOT brand
specific as many headphones are not available where I live.

Having looked around a bit I see varying types ranging from 4 to 600 Ohms
and I would appreciate it very much if somebody could steer me in the right
direction.

I would prefer to use the front Jack and I will be using SSB and working
weak signal stations.

All advice welcome from the group.

Gary
Sent via BlackBerry® from Telstra
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Roy Morris-6

Re: K3 headphones

In reply to this post by rfenabled

Gary,
I use a 33 ohm headset with my K3. I have not noticed any reduction of audio and the impedence match seems to be good. I use an AKG K240 Studio headset and get excellent reproduction. Roy Morris W4WFB
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Brett Howard

Re: K3 headphones

Was it high or low impedance that was causing issues? I'm contemplating
plugging in two pairs of headphones which is probably going to put me
somewhere around 11 to 15 ohms nominal. I'm sure it'll do fine but
hadn't been able to find much in the way of specs for the K3 in this
regard.

On Mon, 2009-06-22 at 11:30 -0400, Roy Morris wrote:

> Gary,
> I use a 33 ohm headset with my K3. I have not noticed any reduction of audio and the impedence match seems to be good. I use an AKG K240 Studio headset and get excellent reproduction. Roy Morris W4WFB
> ______________________________________________________________
> 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

ON4WIX

Re: K3 headphones

Hello Brett,

you could consider using a headphone distribution amp. I purchased this one
for our Region 1 Field Day setup:
http://www.behringer.com/EN/Products/HA400.aspx
It just plugs into one of your K3's headphone sockets and allows you to use
up to 4 sets of headphones simultaneously. Each pair of cans has its own
volume control. Audio and build quality are good as is the price: I bougt
mine for about 30 Euro (21% sales tax included).

Good luck,

Glenn ON4WIX/OR4W

----- Original Message -----
From: "Brett Howard" <[hidden email]>
To: "Roy Morris" <[hidden email]>
Cc: <[hidden email]>
Sent: Monday, June 22, 2009 5:47 PM
Subject: Re: [Elecraft] K3 headphones

> Was it high or low impedance that was causing issues? I'm contemplating
> plugging in two pairs of headphones which is probably going to put me
> somewhere around 11 to 15 ohms nominal. I'm sure it'll do fine but
> hadn't been able to find much in the way of specs for the K3 in this
> regard.
>
>
> On Mon, 2009-06-22 at 11:30 -0400, Roy Morris wrote:
>> Gary,
>> I use a 33 ohm headset with my K3. I have not noticed any reduction of
>> audio and the impedence match seems to be good. I use an AKG K240 Studio
>> headset and get excellent reproduction. Roy Morris W4WFB
>> ______________________________________________________________
>> 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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--------------------------------------------------------------------------------

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KK7P

Re: K3 headphones

In reply to this post by Brett Howard

> ... I'm contemplating
> plugging in two pairs of headphones which is probably going to put me
> somewhere around 11 to 15 ohms nominal. I'm sure it'll do fine but
> hadn't been able to find much in the way of specs for the K3 in this
> regard.

The headphone amplifier in the K3 is designed to drive 32-ohm
headphones. It can drive higher and lower impedances, but the audio
level will be less.

We put 8.2 ohm series resistors at the front jack and again at the rear
jack so plugging in a shorted plug wouldn't kill the audio on the other
jack. As a result, lower impedance phones will have less drive available.

The headphones are *not* attached to the output of the speaker amplifier.

73,

Lyle KK7P

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Joe Subich, W4TV-4

Re: K3 headphones

In reply to this post by Brett Howard

Low impedance headsets are the ones with decreased low end
response - or apparent excessive high frequency response and
the resulting "tiring" sound.

I strongly recommend 200 Ohm (Heil ProSet) or 600 Ohm
(professional) headsets.

73,

... Joe, W4TV

> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Brett Howard
> Sent: Monday, June 22, 2009 11:47 AM
> To: Roy Morris
> Cc: [hidden email]
> Subject: Re: [Elecraft] K3 headphones
>
>
> Was it high or low impedance that was causing issues? I'm
> contemplating plugging in two pairs of headphones which is
> probably going to put me somewhere around 11 to 15 ohms
> nominal. I'm sure it'll do fine but hadn't been able to find
> much in the way of specs for the K3 in this regard.
>
>
> On Mon, 2009-06-22 at 11:30 -0400, Roy Morris wrote:
> > Gary,
> > I use a 33 ohm headset with my K3. I have not noticed any
> reduction of audio and the impedence match seems to be good.
> I use an AKG K240 Studio headset and get excellent
> reproduction. Roy Morris W4WFB
> > ______________________________________________________________
> > 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
>
> ______________________________________________________________
> 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

Brett Howard

Re: K3 headphones

This is not always the case. The headphones that I'm planning on using are
Etymotic ER-4P's which are designed with a low impedance to remain efficient
with portable music players but have very flat responses.

The dip in the top end is intentional as they are sealed into your ear and
they need to put that in so that you don't feel like there is way too much
in the high end. There is much less rolloff when something is sealed into
your ear canal vs outside.

I've made some plots of the ER4s along side the Grado SR60. The Grado is an
often known standard for relatively inexpensive cans with good sound. The
Grado's run around 60 to 80 bucks where as the ER4's are around 300 MSRP.
But you can get them for at least half that.

Response curve:
http://graphs.headphone.com/graphCompare.php?graphType=0&graphID[]=733&graph
ID[]=393
Impedance curve:
http://graphs.headphone.com/graphCompare.php?graphType=7&graphID[]=733&graph
ID[]=393

~Brett

-----Original Message-----
From: Joe Subich, W4TV [mailto:[hidden email]]
Sent: Monday, June 22, 2009 9:36 AM
To: 'Brett Howard'; 'Roy Morris'
Cc: [hidden email]
Subject: RE: [Elecraft] K3 headphones

Low impedance headsets are the ones with decreased low end
response - or apparent excessive high frequency response and
the resulting "tiring" sound.

I strongly recommend 200 Ohm (Heil ProSet) or 600 Ohm
(professional) headsets.

73,

... Joe, W4TV

Joe Subich, W4TV-4

Re: K3 headphones

> This is not always the case. The headphones that I'm
> planning on using are Etymotic ER-4P's which are designed
> with a low impedance to remain efficient with portable music
> players but have very flat responses.

Unfortunately, the 10 uF coupling capacitors in the output of
the K3 headphone amplifier form a voltage divider with the
impedance of the headphones (plus the 8.2 Ohm resistors Lyle
references). For 8 Ohm headphones the -6dB point in the
response is 1 KHz (Xc=16 Ohms). With 200 Ohm phones the -6dB
drops to about 75 Hz (Xc=208 Ohms) and with 600 Ohm phones
the -6dB point drops to about 25 Hz (Xc=608 Ohms).

This is purely a function of the series RC output of the
headphone amplifier and does not effect the speaker
response. K9AC has recommended replacing the 10 uF caps
with 220 uF caps which would reduce the corner frequency
for low impedance headsets to about 50 Hz but since my
primary headset is the Proset I have not tried it as yet.

73,

... Joe, W4TV

> -----Original Message-----
> From: Brett Howard [mailto:[hidden email]]
> Sent: Monday, June 22, 2009 1:52 PM
> To: [hidden email]; 'Roy Morris'
> Cc: [hidden email]
> Subject: RE: [Elecraft] K3 headphones
>
>
> This is not always the case. The headphones that I'm
> planning on using are Etymotic ER-4P's which are designed
> with a low impedance to remain efficient with portable music
> players but have very flat responses.
>
> The dip in the top end is intentional as they are sealed into
> your ear and they need to put that in so that you don't feel
> like there is way too much in the high end. There is much
> less rolloff when something is sealed into your ear canal vs outside.
>
> I've made some plots of the ER4s along side the Grado SR60.
> The Grado is an often known standard for relatively
> inexpensive cans with good sound. The Grado's run around 60
> to 80 bucks where as the ER4's are around 300 MSRP. But you
> can get them for at least half that.
>
> Response curve:
> http://graphs.headphone.com/graphCompare.php?graphType=0&graph
> ID[]=733&graphID[]=393
> Impedance curve:
> http://graphs.headphone.com/graphCompare.php?graphType=7&graph
> ID[]=733&graphID[]=393
>
> ~Brett
>
>
> -----Original Message-----
> From: Joe Subich, W4TV [mailto:[hidden email]]
> Sent: Monday, June 22, 2009 9:36 AM
> To: 'Brett Howard'; 'Roy Morris'
> Cc: [hidden email]
> Subject: RE: [Elecraft] K3 headphones
>
>
> Low impedance headsets are the ones with decreased low end
> response - or apparent excessive high frequency response and
> the resulting "tiring" sound.
>
> I strongly recommend 200 Ohm (Heil ProSet) or 600 Ohm
> (professional) headsets.
>
> 73,
>
> ... Joe, W4TV
>
>
>
>
> > -----Original Message-----
> > From: [hidden email]
> > [mailto:[hidden email]] On Behalf Of Brett Howard
> > Sent: Monday, June 22, 2009 11:47 AM
> > To: Roy Morris
> > Cc: [hidden email]
> > Subject: Re: [Elecraft] K3 headphones
> >
> >
> > Was it high or low impedance that was causing issues? I'm
> > contemplating plugging in two pairs of headphones which is
> > probably going to put me somewhere around 11 to 15 ohms
> > nominal. I'm sure it'll do fine but hadn't been able to find
> > much in the way of specs for the K3 in this regard.
> >
> >
> > On Mon, 2009-06-22 at 11:30 -0400, Roy Morris wrote:
> > > Gary,
> > > I use a 33 ohm headset with my K3. I have not noticed any
> > reduction of audio and the impedence match seems to be good.
> > I use an AKG K240 Studio headset and get excellent
> > reproduction. Roy Morris W4WFB
> > > ______________________________________________________________
> > > 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
> >
> > ______________________________________________________________
> > 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
>
>

Brett Howard

Re: K3 headphones

Looks like I'm going to have some issues going with that direct... My
27 ohm headphones weren't really faithfully reproducing what was there
on the speakers out the back.

Guess I'll just borrow my wife's headphone amplifier from work. The amp
that I use at in my office is still in a bread board and isn't field day
tough. The input impedance to the amp that she has is 18Kohms that
should be plenty high.

Here's what I plan on using...
http://www.headphone.com/products/headphone-amps/headphone-amp-list/headroom-total-airhead.php

Wonder if the crossfeed feature on that amp will be something that I
like when listening to the SubRX. Perhaps if its good thats something
that can be added to the software.

Thanks much for the input gentlemen.

~Brett

On Mon, 2009-06-22 at 16:33 -0400, Joe Subich, W4TV wrote:

> > This is not always the case. The headphones that I'm
> > planning on using are Etymotic ER-4P's which are designed
> > with a low impedance to remain efficient with portable music
> > players but have very flat responses.
>
> Unfortunately, the 10 uF coupling capacitors in the output of
> the K3 headphone amplifier form a voltage divider with the
> impedance of the headphones (plus the 8.2 Ohm resistors Lyle
> references). For 8 Ohm headphones the -6dB point in the
> response is 1 KHz (Xc=16 Ohms). With 200 Ohm phones the -6dB
> drops to about 75 Hz (Xc=208 Ohms) and with 600 Ohm phones
> the -6dB point drops to about 25 Hz (Xc=608 Ohms).
>
> This is purely a function of the series RC output of the
> headphone amplifier and does not effect the speaker
> response. K9AC has recommended replacing the 10 uF caps
> with 220 uF caps which would reduce the corner frequency
> for low impedance headsets to about 50 Hz but since my
> primary headset is the Proset I have not tried it as yet.
>
> 73,
>
> ... Joe, W4TV
>
>
>
> > -----Original Message-----
> > From: Brett Howard [mailto:[hidden email]]
> > Sent: Monday, June 22, 2009 1:52 PM
> > To: [hidden email]; 'Roy Morris'
> > Cc: [hidden email]
> > Subject: RE: [Elecraft] K3 headphones
> >
> >
> > This is not always the case. The headphones that I'm
> > planning on using are Etymotic ER-4P's which are designed
> > with a low impedance to remain efficient with portable music
> > players but have very flat responses.
> >
> > The dip in the top end is intentional as they are sealed into
> > your ear and they need to put that in so that you don't feel
> > like there is way too much in the high end. There is much
> > less rolloff when something is sealed into your ear canal vs outside.
> >
> > I've made some plots of the ER4s along side the Grado SR60.
> > The Grado is an often known standard for relatively
> > inexpensive cans with good sound. The Grado's run around 60
> > to 80 bucks where as the ER4's are around 300 MSRP. But you
> > can get them for at least half that.
> >
> > Response curve:
> > http://graphs.headphone.com/graphCompare.php?graphType=0&graph
> > ID[]=733&graphID[]=393
> > Impedance curve:
> > http://graphs.headphone.com/graphCompare.php?graphType=7&graph
> > ID[]=733&graphID[]=393
> >
> > ~Brett
> >
> >
> > -----Original Message-----
> > From: Joe Subich, W4TV [mailto:[hidden email]]
> > Sent: Monday, June 22, 2009 9:36 AM
> > To: 'Brett Howard'; 'Roy Morris'
> > Cc: [hidden email]
> > Subject: RE: [Elecraft] K3 headphones
> >
> >
> > Low impedance headsets are the ones with decreased low end
> > response - or apparent excessive high frequency response and
> > the resulting "tiring" sound.
> >
> > I strongly recommend 200 Ohm (Heil ProSet) or 600 Ohm
> > (professional) headsets.
> >
> > 73,
> >
> > ... Joe, W4TV
> >
> >
> >
> >
> > > -----Original Message-----
> > > From: [hidden email]
> > > [mailto:[hidden email]] On Behalf Of Brett Howard
> > > Sent: Monday, June 22, 2009 11:47 AM
> > > To: Roy Morris
> > > Cc: [hidden email]
> > > Subject: Re: [Elecraft] K3 headphones
> > >
> > >
> > > Was it high or low impedance that was causing issues? I'm
> > > contemplating plugging in two pairs of headphones which is
> > > probably going to put me somewhere around 11 to 15 ohms
> > > nominal. I'm sure it'll do fine but hadn't been able to find
> > > much in the way of specs for the K3 in this regard.
> > >
> > >
> > > On Mon, 2009-06-22 at 11:30 -0400, Roy Morris wrote:
> > > > Gary,
> > > > I use a 33 ohm headset with my K3. I have not noticed any
> > > reduction of audio and the impedence match seems to be good.
> > > I use an AKG K240 Studio headset and get excellent
> > > reproduction. Roy Morris W4WFB
> > > > ______________________________________________________________
> > > > 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
> > >
> > > ______________________________________________________________
> > > 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
> >
> >
>

Alexander Ponomarenko-5

Re: K3 headphones

In reply to this post by Joe Subich, W4TV-4

I has tried replacing the 10uF caps with 100uF in AF-amp, also in
data-sheet for LM4811MM we see grounded pin 10 have to add for 1uF cap.
The result is excellent with my ProSet.
Sound clean and deep. Signals became more raised, proturberant, appeared
"body of the sound", clearly differ the most small details in signals.
Such sensation, that earlier the signals got through blanket,
but now here is they, straight before my eyes, and they proturberant and
volumetric.
As my ears as SpectroLab also "sees the difference". You can see my
plots "before" and "after" same mods.

before mods: http://forum.cqham.ru/download.php?id=43281
after mods: http://forum.cqham.ru/download.php?id=43282

before s9 level: http://forum.cqham.ru/download.php?id=43279
after s9 level: http://forum.cqham.ru/download.php?id=43280

73! Alex UR5LAM

Joe Subich, W4TV:
>> K9AC has recommended replacing the 10 uF caps
>> with 220 uF caps which would reduce the corner frequency
>> for low impedance headsets to about 50 Hz but since my
>> primary headset is the Proset I have not tried it as yet.
>>
>> 73,
>>
>> ... Joe, W4TV
>>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Brett Howard

Re: K3 headphones

Where are these caps? I see them on page 28 of 52 on the schematics but
where do they physically live in the unit. I assume they are on the main
DSP board. Also as far as the "grounded 1uF cap" are you talking about the
lil decoupling nugget they had sitting there? Guess it couldn't hurt...

Your pictures say after AF and IF amplifier modifications. What IF mods did
you make?

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Alexander Ponomarenko
Sent: Tuesday, June 23, 2009 12:16 AM
To: [hidden email]
Subject: Re: [Elecraft] K3 headphones

I has tried replacing the 10uF caps with 100uF in AF-amp, also in
data-sheet for LM4811MM we see grounded pin 10 have to add for 1uF cap.
The result is excellent with my ProSet.
Sound clean and deep. Signals became more raised, proturberant, appeared
"body of the sound", clearly differ the most small details in signals.
Such sensation, that earlier the signals got through blanket,
but now here is they, straight before my eyes, and they proturberant and
volumetric.
As my ears as SpectroLab also "sees the difference". You can see my
plots "before" and "after" same mods.

before mods: http://forum.cqham.ru/download.php?id=43281
after mods: http://forum.cqham.ru/download.php?id=43282

before s9 level: http://forum.cqham.ru/download.php?id=43279
after s9 level: http://forum.cqham.ru/download.php?id=43280

73! Alex UR5LAM

Joe Subich, W4TV:
>> K9AC has recommended replacing the 10 uF caps
>> with 220 uF caps which would reduce the corner frequency
>> for low impedance headsets to about 50 Hz but since my
>> primary headset is the Proset I have not tried it as yet.
>>
>> 73,
>>
>> ... Joe, W4TV
>>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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______________________________________________________________
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Alexander Ponomarenko-5

Re: K3 headphones

These caps - near Front Panel Phone Out. C9=C13=100uF 10V
Also add 1uF: "+" to pin 10 U2; "-" to ground. Picture here:
C9 and C13: http://forum.cqham.ru/files/thumbs/t_img_0011_824.jpg
new 1uF cap: http://forum.cqham.ru/files/thumbs/t_img_0010_282.jpg

Yes, IF buffer amplifier also have to be modified. Using only
electrolytic caps C84 and C92 not is enough, they must be bypass
by ceramic caps.
Photo: http://forum.cqham.ru/files/thumbs/t_img_0009_928.jpg

All these modifications are not simply. I think the best way to
settlements of the problems call to Elecraft Tech. Support and Repairs.

73! Alex UR5LAM

Brett Howard:

> Where are these caps? I see them on page 28 of 52 on the schematics but
> where do they physically live in the unit. I assume they are on the main
> DSP board. Also as far as the "grounded 1uF cap" are you talking about the
> lil decoupling nugget they had sitting there? Guess it couldn't hurt...
>
> Your pictures say after AF and IF amplifier modifications. What IF mods did
> you make?
>
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Alexander Ponomarenko
> Sent: Tuesday, June 23, 2009 12:16 AM
> To: [hidden email]
> Subject: Re: [Elecraft] K3 headphones
>
> I has tried replacing the 10uF caps with 100uF in AF-amp, also in
> data-sheet for LM4811MM we see grounded pin 10 have to add for 1uF cap.
> The result is excellent with my ProSet.
> Sound clean and deep. Signals became more raised, proturberant, appeared
> "body of the sound", clearly differ the most small details in signals.
> Such sensation, that earlier the signals got through blanket,
> but now here is they, straight before my eyes, and they proturberant and
> volumetric.
> As my ears as SpectroLab also "sees the difference". You can see my
> plots "before" and "after" same mods.
>
> before mods: http://forum.cqham.ru/download.php?id=43281
> after mods: http://forum.cqham.ru/download.php?id=43282
>
> before s9 level: http://forum.cqham.ru/download.php?id=43279
> after s9 level: http://forum.cqham.ru/download.php?id=43280
>
> 73! Alex UR5LAM
>
> Joe Subich, W4TV:
>>> K9AC has recommended replacing the 10 uF caps
>>> with 220 uF caps which would reduce the corner frequency
>>> for low impedance headsets to about 50 Hz but since my
>>> primary headset is the Proset I have not tried it as yet.
>>>
>>> 73,
>>>
>>> ... Joe, W4TV
>>>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
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>
>

Alexander Ponomarenko-5

Re: K3 headphones

In reply to this post by Brett Howard

These caps - near Front Panel Phone Out. C9=C13=100uF 10V
Also add 1uF: "+" to pin 10 U2; "-" to ground. Picture here:
C9 and C13: http://forum.cqham.ru/download.php?id=43285 (big photo)
new 1uF cap: http://forum.cqham.ru/download.php?id=43286 (big photo)

Yes, IF buffer amplifier also have to be modified. Using only
electrolytic caps C84 and C92 not is enough, they must be bypass
by ceramic caps.
Photo: http://forum.cqham.ru/download.php?id=43287 (big photo)
All these modifications are not simply. I think the best way to
settlements of the problems call to Elecraft Tech. Support and Repairs.

73! Alex UR5LAM

Brett Howard:

P.B. Christensen

Re: K3 headphones

In reply to this post by Alexander Ponomarenko-5

>> I has tried replacing the 10uF caps with 100uF in AF-amp, also in
>> data-sheet for LM4811MM we see grounded pin 10 have to add for 1uF cap.
>> The result is excellent with my ProSet.

If anyone is going through the trouble of changing the 10uF caps at C9 and
C13 on the front panel DSP Board, I suggest going to 330 uF to ensure that a
broad range of headphones are covered, including old models with fairly Lo-Z
drivers.

http://www.n1eu.com/K3/k3audiomod.htm

The National LM4811MM spec sheet notes that the bypass cap (Cb) value as
described above is critical with respect to turn-on clicks and pops.

>From the data sheet:
"Capacitor Cb is the most critical component to minimize turn on pops since
it determines how fast the LM4811 turns on."

It's already at 10 uF. Before changing it, I would test for clicks/pops
both ways to ensure that artifacts are not present.

Paul, W9AC

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Alexander Ponomarenko-5

Re: K3 headphones

Paul, don't touch C22 cap (Cb for pin3 "bypass")!
You can to add 1uF cap to VDD line (U2 pin10).

Alex UR5LAM

Paul Christensen пишет:

> The National LM4811MM spec sheet notes that the bypass cap (Cb) value as
> described above is critical with respect to turn-on clicks and pops.
>
>>From the data sheet:
> "Capacitor Cb is the most critical component to minimize turn on pops since
> it determines how fast the LM4811 turns on."
>
> It's already at 10 uF. Before changing it, I would test for clicks/pops
> both ways to ensure that artifacts are not present.
>
> Paul, W9AC

Brett Howard

Re: K3 headphones

In reply to this post by Alexander Ponomarenko-5

So if you're doing C84 and C92 why not also C82 and C90?

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Alexander Ponomarenko
Sent: Tuesday, June 23, 2009 12:54 PM
Cc: [hidden email]
Subject: Re: [Elecraft] K3 headphones

These caps - near Front Panel Phone Out. C9=C13=100uF 10V
Also add 1uF: "+" to pin 10 U2; "-" to ground. Picture here:
C9 and C13: http://forum.cqham.ru/download.php?id=43285 (big photo)
new 1uF cap: http://forum.cqham.ru/download.php?id=43286 (big photo)

Yes, IF buffer amplifier also have to be modified. Using only
electrolytic caps C84 and C92 not is enough, they must be bypass
by ceramic caps.
Photo: http://forum.cqham.ru/download.php?id=43287 (big photo)
All these modifications are not simply. I think the best way to
settlements of the problems call to Elecraft Tech. Support and Repairs.

73! Alex UR5LAM

Brett Howard:
> Where are these caps? I see them on page 28 of 52 on the schematics but
> where do they physically live in the unit. I assume they are on the main
> DSP board. Also as far as the "grounded 1uF cap" are you talking about
the
> lil decoupling nugget they had sitting there? Guess it couldn't hurt...
>
> Your pictures say after AF and IF amplifier modifications. What IF mods
did
> you make?
>
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Alexander
Ponomarenko

> Sent: Tuesday, June 23, 2009 12:16 AM
> To: [hidden email]
> Subject: Re: [Elecraft] K3 headphones
>
> I has tried replacing the 10uF caps with 100uF in AF-amp, also in
> data-sheet for LM4811MM we see grounded pin 10 have to add for 1uF cap.
> The result is excellent with my ProSet.
> Sound clean and deep. Signals became more raised, proturberant, appeared
> "body of the sound", clearly differ the most small details in signals.
> Such sensation, that earlier the signals got through blanket,
> but now here is they, straight before my eyes, and they proturberant and
> volumetric.
> As my ears as SpectroLab also "sees the difference". You can see my
> plots "before" and "after" same mods.
>
> before mods: http://forum.cqham.ru/download.php?id=43281
> after mods: http://forum.cqham.ru/download.php?id=43282
>
> before s9 level: http://forum.cqham.ru/download.php?id=43279
> after s9 level: http://forum.cqham.ru/download.php?id=43280
>
> 73! Alex UR5LAM
>
> Joe Subich, W4TV:
>>> K9AC has recommended replacing the 10 uF caps
>>> with 220 uF caps which would reduce the corner frequency
>>> for low impedance headsets to about 50 Hz but since my
>>> primary headset is the Proset I have not tried it as yet.
>>>
>>> 73,
>>>
>>> ... Joe, W4TV
>>>
>
> ______________________________________________________________
> 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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W8ZN

K3 - TX gate issue

In reply to this post by Alexander Ponomarenko-5

Has anyone else noticed some distortion using the tx gate option? I heard it
on a friends' K3 and tested it on mine, while listening on headphones and
the monitor on, after each word or syllable, I hear some distortion or
"crackling" noise. It seems to be when the setting is at 13 or above. I've
heard it on 3 different K3's of different vintages but all running 3.19.

Terry

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Stewart Baker

Re: K3 - TX gate issue

I have it on my K3. Slight, but noticeable.

Stewart G3RXQ
On Sun, 12 Jul 2009 23:13:50 -0400, Terry Price wrote:
>
> Has anyone else noticed some distortion using the tx gate
option? I heard it
> on a friends' K3 and tested it on mine, while listening on
headphones and
> the monitor on, after each word or syllable, I hear some
distortion or
> "crackling" noise. It seems to be when the setting is at 13 or
above. I've
> heard it on 3 different K3's of different vintages but all
running 3.19.

>
> Terry
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
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>
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> Please help support this email list:

http://www.qsl.net/donate.html

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pd0psb

Re: K3 - TX gate issue

The TX gate is a fast-switching "hard gate" so it will quickly open/close around its threshhold, that is the crackling you hear. A delay of its closing time or soft-knee behaviour would avoid this.

Try setting it in such away that the switching threshold is not too near to the ground-noise you want to supress. (threshhold higher/mic gain slightly lower)
Note: The action of the TX gate can only be monitored on-air, its action is not outputted through K3 internal monitoring!

73'
Paul
PD0PSB

after each word or syllable, I hear some
distortion or
> "crackling" noise.