Audio Volume

[Jim Harris-4]

Hi Folks,

As has been mentioned by other on this forum
previously my K2 also seems to be in need of a boost
in overall audio volume.  Is there a modification that
can be made to increase the volume?

My hearing is not great.  The fact that the speaker is
oriented up instead of forward doesn't help.  When I
put the DSP in I usually have to boost the AF Gain
about a quarter turn.  It's not unusualy to have it
maxed out.  The RF Gain is always max clockwise.  Most
headphones available are 8-32 ohms so switching to
headphones only eliminates some outside noise and
doesn't increase the volume and in fact usually
decreases it.  The speaker is 4 ohms so changing the
speaker to a lower resistance (if available) is likely
not an option.  I get and give good signal reports and
have what I believe are good antennas....they seem to
perform fine with my other HF rig.  The K2 has the
cleaner and brighter audio with less noise.

If there is not a way to boost the audio my latest
thought is to purchase an external DSP amplified
speaker with a headphone jack.  I had rather not do
that as they start at over $100 and up to $250.  Any
thought or ideas would be helpful and appreciated.
Off forum email replys are fine.

Thanks and have a great day!

Jim, AB0UK
K2,  SN 4787



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[Don Wilhelm-3]

Jim,

Unless your hearing is really poor, you have a problem with your K2 - even
one with weak audio will provide adequate audio with the AF gain somewhere
between the 9 o'clock and the 12 o'clock position unless the room noise is
quite high.  It does not have the reserve audio or raw audio power that many
other transceivers do, but it is adequate for most situations.

First, if you have to advance the AF gain when the KDSP2 is turned on, you
may want to look for a problem with the KSDP2.  Normally, the KDSP2 adds a
small amount of additional audio gain when it is installed.

Secondly,  be certain your K2 is tuned up correctly - especially the filter
adjustments.  The proper positioning of the passband will go a long way to
improving the K2 audio output volume.

If you have an older K2 (pre-SN 3000), install the new AF Gain control
wiring - and if you have an even older K2, check the number of turns on T7 -
if it has the ratio of 11:3 turns, rewind it for the new ratio of 20:5
turns.

I believe there is a list of other things to check from Gary Surrency
available on the Elecraft website.

If you still need additional audio amplification, you may want to check out
one of the amplified Motorola external speakers often available on E-bay.
See Tom Hammond's website www.n0ss.net for additional information on these
speakers.  You could also consider building one of the SP2 external
speakers - details at www.elecraft.com - it did not make it as a product,
but the details are there should you want to partake of them.

73,
Don W3FPR

> -----Original Message-----
>
> As has been mentioned by other on this forum
> previously my K2 also seems to be in need of a boost
> in overall audio volume.  Is there a modification that
> can be made to increase the volume?
>
> My hearing is not great.  The fact that the speaker is
> oriented up instead of forward doesn't help.  When I
> put the DSP in I usually have to boost the AF Gain
> about a quarter turn.  It's not unusualy to have it
> maxed out.  The RF Gain is always max clockwise.  Most
> headphones available are 8-32 ohms so switching to
> headphones only eliminates some outside noise and
> doesn't increase the volume and in fact usually
> decreases it.  The speaker is 4 ohms so changing the
> speaker to a lower resistance (if available) is likely
> not an option.  I get and give good signal reports and
> have what I believe are good antennas....they seem to
> perform fine with my other HF rig.  The K2 has the
> cleaner and brighter audio with less noise.
>
>

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[Tom Bosscher]

Jim Harris wrote:
  Is there a modification that
> can be made to increase the volume?
>
       
        Jim,

        Two things. Make sure your AGC is set correctly. Once set, even with
the built in speaker of the K2, you can fill the room with the volume
control at 10 o'clock.

        Then, it may be big, and it's not cheap, but that "Sounds Sweet"
speaker is one very efficient speaker. I have it about two feet to the
left of the K2, pointed at me, and between it and the K2, there is too
much audio gain. All my volume control range I need is within the first
45 degrees. I almost am ready to lower the gain inside. And I am using
the DSP module. Also, if there is drop in audio using the DSP module,
there is a gain setting to reset that. Look in the archives or ask Dr.
Elecraft, W3FPR!

        73, de tom bosscher k8tb

sounds sweet is at:

http://www.soundssweet.com/

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[Don Wilhelm-3]

 Also, if there is drop in audio using the DSP module,
> there is a gain setting to reset that. Look in the archives or ask Dr.
> Elecraft, W3FPR!
>
> 73, de tom bosscher k8tb
>
-----------------------------------------------------

Thanks for the title Tom!  I am honored.
But the KDSP2 is one thing I have not gotten into closely, so please direct
the KDSP2 questions to Gary (mailto:[hidden email]) or Lyle Johnson
(the guy designed it).

In my quick reply earlier, I failed to mention the AGC setting - even if it
is set for the manual recommendation of 3.8 volts, it may be too high and
hold the gain down.  Test by turning the AGC off and on with no signals on
the band (if band noise is present, disconnect the antenna), and make
certain the DSP de-noiser is not running.  If you hear a change in the noise
level, the AGC Threshold is set too high.  I have seen some K2s which needed
the AGC Threshold reduced to 3.65 volts, but most I have encountered do well
at somewhere between 3.7 and 3.8 volts.  Don't forget to reset CAL S Lo and
CAL S Hi after changing the AGC Threshold if you want your S-meter to
indicate over its full scale.

73,
Don W3FPR
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[Jim Brown-10]

On Fri, 29 Apr 2005 07:54:22 -0700 (PDT), Jim Harris wrote:

>As has been mentioned by other on this forum
>previously my K2 also seems to be in need of a boost
>in overall audio volume.

As an audio professional and long time ham, I would do three
things.

1) Look carefully through the audio chain and the AGC to make sure
there isn't some problem that is causing low audio gain. My two
K2's have plenty of gain, but the one that I bought six months ago
came with a couple of solder bridges that screwed up the audio.
One problem was on the control board, the other on the DSP board.

2) The setup menu for the KDSP2 includes settings for audio gain
with and without the DSP engaged. I generally set both for a few
dB of gain.

3) The K2 loudspeaker is a pretty efficient one, and I doubt that
you will easily find one that is more efficient. I've picked up
some little "cube" loudspeakers at hamfests that improve other
radios, but it does not improve the K2. In general, small
loudspeakers have poor efficiency. If you want more level, look
for a much larger loudspeaker, and try to choose a 4 ohm
loudspeaker designed for sound reinforcement use. Hi-fi
loudspeakers are generally poor choices -- they compromise
efficiency for sound quality.

FWIW, I generally prefer to do my serious operating with
headphones, and every set of cans I've ever tried give me plenty
of level with the K2.

Jim Brown  K9YC


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[Stuart Rohre]

Make sure your speaker bolts are not overly tight distorting the speaker
voice coil travel.  This was a problem on a number of units.

An idea:   cut some spacers that are beveled so as to tilt the speaker
forward.  They cannot be long, as you will get a tunnel stove pipe effect if
the speaker is too low under the cover.  But maybe you can tilt the speaker
enough to help.  An external speaker is always better.
72,
Stuart
K5KVH



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[Margaret Leber]

W3FPR - Don Wilhelm wrote:

> In my quick reply earlier, I failed to mention the AGC setting - even if it
> is set for the manual recommendation of 3.8 volts, it may be too high and
> hold the gain down.  Test by turning the AGC off and on with no signals on
> the band (if band noise is present, disconnect the antenna), and make
> certain the DSP de-noiser is not running.  If you hear a change in the noise
> level, the AGC Threshold is set too high.

Imagine my surprise in discovering that later K2s have an adjustable AGC
threshold. ;-) *My* control board R1 is a 51K ohm fixed resistor ;-)

For those following the saga of K2 1641, it's pretty much completely in
operation. I need to retweak the 20m BPF a bit, but otherwise it's
rockin' out. Doing Don's AGC on/off test above might give an
almost-perceptible change in noise level, I'm not sure. Doesn't seem
like an issue.

It works better than my CW does, anyway....gotta work on that.

Now I have the battery and SSB mods to work on. We'll see how well the
battery has weathered several years storage; it may well need to be
replaced.

73 de Maggie K3XS

--
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----/(, /|  /| http://voicenet.com/~maggie SCWCD/ is to preserve order/
---/   / | / |  _   _   _    `  _  AOPA 925383/ amid change and to  /
--/ ) /  |/  |_(_(_(_/_(_/__(__(/_      K3XS / preserve change amid/
-/ (_/   '        .-/ .-/        ARRL 39280 /order."-A.N.Whitehead/
/________________(_/_(_/_______AMSAT 32844_/<[hidden email]>/

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[Ron D'Eau Claire-2]

Stuart, K5KVH, wrote:
Make sure your speaker bolts are not overly tight distorting the speaker
voice coil travel.  This was a problem on a number of units.

Reply: ----------------

BENT SPEAKER

Some speakers arrived at the builder bent so the voice coil rubbed, but that
was pretty obvious and not just a low-volume issue. Even CW tones were
obviously distorted. Mine was one of those, and I found it was very easy to
bend the frame. Indeed I fixed it that way with a large screwdriver to gain
leverage between the edge of the magnet and the frame!

Apparently during travel somewhere between China, where it was made, and
Oregon via Aptos and other places unknown, the speaker was subjected to
enough shock to bend the frame. After messing with it I have no doubt that
would be easy to bend the frame by dropping the speaker, in its padded box,
from a perfectly typical height encountered in shipping that would produce
no other indication that the box or the speaker had been abused. It takes
very little force at all. The weight of the heavy magnet suddenly "stopping"
does the bending.

Like the problem with over-tightening the bolts, it's all a matter of a very
light-weight and bendable metal frame on the speaker.

MORE VOLUME

If there's nothing on top of the K2, one can make a significant increase in
the volume for a listener in front of the radio by simply providing a
reflector. A stiff piece of paper shaped in a curve and angled over the
speaker opening so the sound bounces off and forward will make a big
difference.

My impression of the post that started this thread was that the operator
needed more than a doubling or tripling of the audio level though. I'm
inclined to agree with those who suggested that there is something wrong in
the audio channel of his K2.

Ron AC7AC


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[Phil LaMarche]

Ron,

I too am hard of hearing and have tried many speakers, the best being Sounds
Sweet. All of those required 3/4 to full AF.  My K2 is on the second shelf
and I never use the internal speaker from any radio.  Tom Hammond, N0SS,
built for me the project speaker mounted in the Elecraft cabinet.  He added
an amplifier. It WORKS wonderful.  1/4 turn of the AF and it's perfect.  I
couldn't be happier.

Phil

Philip LaMarche
Instant Gourmet
LaMarche Enterprises, Inc.
www.instantgourmetspices.com
727-944-3226
727-937-8834 Fax
727-510-5038 Cell
NASFT # 30210
W9DVM

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Ron D'Eau Claire
Sent: Friday, April 29, 2005 3:14 PM
To: 'Elecraft'
Subject: RE: [Elecraft] Audio Volume

Stuart, K5KVH, wrote:
Make sure your speaker bolts are not overly tight distorting the speaker
voice coil travel.  This was a problem on a number of units.

Reply: ----------------

BENT SPEAKER

Some speakers arrived at the builder bent so the voice coil rubbed, but that
was pretty obvious and not just a low-volume issue. Even CW tones were
obviously distorted. Mine was one of those, and I found it was very easy to
bend the frame. Indeed I fixed it that way with a large screwdriver to gain
leverage between the edge of the magnet and the frame!

Apparently during travel somewhere between China, where it was made, and
Oregon via Aptos and other places unknown, the speaker was subjected to
enough shock to bend the frame. After messing with it I have no doubt that
would be easy to bend the frame by dropping the speaker, in its padded box,
from a perfectly typical height encountered in shipping that would produce
no other indication that the box or the speaker had been abused. It takes
very little force at all. The weight of the heavy magnet suddenly "stopping"
does the bending.

Like the problem with over-tightening the bolts, it's all a matter of a very
light-weight and bendable metal frame on the speaker.

MORE VOLUME

If there's nothing on top of the K2, one can make a significant increase in
the volume for a listener in front of the radio by simply providing a
reflector. A stiff piece of paper shaped in a curve and angled over the
speaker opening so the sound bounces off and forward will make a big
difference.

My impression of the post that started this thread was that the operator
needed more than a doubling or tripling of the audio level though. I'm
inclined to agree with those who suggested that there is something wrong in
the audio channel of his K2.

Ron AC7AC


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[Ron D'Eau Claire-2]

Phil, W9DVM wrote:
I too am hard of hearing and have tried many speakers, the best being Sounds
Sweet. All of those required 3/4 to full AF.  My K2 is on the second shelf
and I never use the internal speaker from any radio.  Tom Hammond, N0SS,
built for me the project speaker mounted in the Elecraft cabinet.  He added
an amplifier. It WORKS wonderful.  1/4 turn of the AF and it's perfect.  I
couldn't be happier.

Reply: --------------------------------

That's great! It's good to remember that the K2 is a low-current-drain
design so people using the QRP version can get the most out of a battery
supply.

LOW CURRENT AUDIO OUTPUT

One of the design considerations to minimize the current drain was in the
amount of audio power it'd provide at the speaker/phones jack. A low-current
audio output I.C was chosen on purpose. It has plenty of audio for *most*
people in normal hamshack environments. It's not enough audio for other
situations though. For example, there have been a number of comments that it
doesn't work well in a noisy automobile under way.

I'm not at all surprised to hear that if you are hard of hearing and find
the internal speaker of most radios lacking that the K2 wouldn't be able to
make enough sound either.

PHONES

One thing about the phones output that comes up from time to time too is
that the design includes resistors in series with the phones. It assumes a
"computer" type of phones will be used with an impedance of 30 to 50 ohms.
Those resistors can severely limit the audio level if low-impedance (4 - 16
ohm) phones are used.

Ron AC7AC



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[n6wg]

Jim
I use the old Timewave DSP 59+ external unit for several reasons.
My acoustic filter speaker isn't real efficient, and the K2 doesn't
drive it to the volume I would like.  So, the DSP unit provides
extra amplification to drive the speaker.  In addition, the DSP filtering
supplements the K2 filtering.  However, with the K2 crystal filters
and the internal DSP option, I seldom need additional filtering.
Another feature of the external unit that I use a lot is the AGC
function.  If you are using headphones, listening to a weak station
and suddenly a strong local comes on calling him, you get a great blast
of noise in the headphones, and it hurts.  The AGC option clamps down
on this and saves my ears, so I use it a lot too, especially in
contests.
Hope this helps, Jim.
Good luck and 73
Bob N6WG

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]]On Behalf Of Jim Harris
Sent: Friday, April 29, 2005 7:54 AM
To: Elecraft
Subject: [Elecraft] Audio Volume


Hi Folks,

As has been mentioned by other on this forum
previously my K2 also seems to be in need of a boost
in overall audio volume.  Is there a modification that
can be made to increase the volume?

My hearing is not great.  The fact that the speaker is
oriented up instead of forward doesn't help.  When I
put the DSP in I usually have to boost the AF Gain
about a quarter turn.  It's not unusualy to have it
maxed out.  The RF Gain is always max clockwise.  Most
headphones available are 8-32 ohms so switching to
headphones only eliminates some outside noise and
doesn't increase the volume and in fact usually
decreases it.  The speaker is 4 ohms so changing the
speaker to a lower resistance (if available) is likely
not an option.  I get and give good signal reports and
have what I believe are good antennas....they seem to
perform fine with my other HF rig.  The K2 has the
cleaner and brighter audio with less noise.

If there is not a way to boost the audio my latest
thought is to purchase an external DSP amplified
speaker with a headphone jack.  I had rather not do
that as they start at over $100 and up to $250.  Any
thought or ideas would be helpful and appreciated.
Off forum email replys are fine.

Thanks and have a great day!

Jim, AB0UK
K2,  SN 4787



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