Headphone output levels on the K2?

[Steve Kallal]

Hello again!

I have a requirement that my rigs have relatively high audio output wo/
distortion from the headphone jack. I have a moderate hearing loss, about 45
db down especially in the speech region. The audiologists calls that
MODERATE. 60 db down is considered more serious. Wow! Even the FCC wants tx
spurs down 40 db or so.

I have been using a FlexRadio SDR-1000 rig mostly because of the great DSP.
One of the advantages is the external Firewire sound card which is able to
boost audio into the headphones. I even found a cheap set of KOSS UR29
headphones have more output than my Heil's. The headphone output on the PRO
II causes the headphone audio to distort before its loud enough for me.

But the simplicity of CW seems wasted on a lot of hardware hanging off a PC.
I am a new CW op. Started last fall getting my code speed up after 31 years
as a ham and 29 years on HF. Do about 15 wpm on a good day. A friend of mine
thinks the K2 is a good rig for copying weak CW popping through the QRN. The
SDR is the best I've found so far. It certainly puts my PRO II to shame on
rx.

I think the best thing about a kit like the K2 is that adding a small audio
stage internally before the headphone jack doesn't ruin the rig. But I would
hope that won't be necessary.

Also I don't wear my hearing aids with headphones because of feeback. I went
with behind the ear hearing aids. Maybe a heaphones with larger deeper cups
would help.

I welcome comments from those who are familiar with the headphone output
level on the K2. I don't want to drag around some external mixer to listen
to CW, hi hi.

73,

Steve N6VL
FISTS #12707
SKCC #2383
 
[hidden email]

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[Brett gazdzinski-2]

 
I have an old set of full size sony headphones
that give way more than enough audio output
for my moderate hearing loss.
Most headphones are rated for the level of audio out
for power in, and the ones that cover the ears seem to be
more comfortable for me and reduce any outside noise.


How you set up the agc effects the audio output level
of the k2, and there are resistors that can be changed
or eliminated in the headphone circuit, or you
could plug the headphones in the ext speaker output.

You can also change the tone of the CW to get in a range that
you might hear better, I seem to like a much higher CW
note than many operators as I am up against the BFO range
limit on my K2.

Brett
N2DTS

> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Steve Kallal
> Sent: Monday, June 11, 2007 11:16 AM
> To: [hidden email]
> Subject: [Elecraft] Headphone output levels on the K2?
>
> Hello again!
>
> I have a requirement that my rigs have relatively high audio
> output wo/
> distortion from the headphone jack. I have a moderate hearing
> loss, about 45
> db down especially in the speech region. The audiologists calls that
> MODERATE. 60 db down is considered more serious. Wow! Even
> the FCC wants tx
> spurs down 40 db or so.
>
> I have been using a FlexRadio SDR-1000 rig mostly because of
> the great DSP.
> One of the advantages is the external Firewire sound card
> which is able to
> boost audio into the headphones. I even found a cheap set of KOSS UR29
> headphones have more output than my Heil's. The headphone
> output on the PRO
> II causes the headphone audio to distort before its loud
> enough for me.
>
> But the simplicity of CW seems wasted on a lot of hardware
> hanging off a PC.
> I am a new CW op. Started last fall getting my code speed up
> after 31 years
> as a ham and 29 years on HF. Do about 15 wpm on a good day. A
> friend of mine
> thinks the K2 is a good rig for copying weak CW popping
> through the QRN. The
> SDR is the best I've found so far. It certainly puts my PRO
> II to shame on
> rx.
>
> I think the best thing about a kit like the K2 is that adding
> a small audio
> stage internally before the headphone jack doesn't ruin the
> rig. But I would
> hope that won't be necessary.
>
> Also I don't wear my hearing aids with headphones because of
> feeback. I went
> with behind the ear hearing aids. Maybe a heaphones with
> larger deeper cups
> would help.
>
> I welcome comments from those who are familiar with the
> headphone output
> level on the K2. I don't want to drag around some external
> mixer to listen
> to CW, hi hi.
>
> 73,
>
> Steve N6VL
> FISTS #12707
> SKCC #2383
>  
> [hidden email]
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft   
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>

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[David Woolley (E.L)]

Steve Kallal wrote:
> I have a requirement that my rigs have relatively high audio output wo/
> distortion from the headphone jack. I have a moderate hearing loss, about 45
> db down especially in the speech region. The audiologists calls that

I've had that sort of loss in one ear since childhood and some in the
other, and I did get prescribed an aid as a child, although I haven't
been very good at using it.

>
> I think the best thing about a kit like the K2 is that adding a small audio
> stage internally before the headphone jack doesn't ruin the rig. But I would
> hope that won't be necessary.

As others have said, you could also reduce the series resistors on the
headphone output, although you might need to modify the shunt capacitors
as well; I'm not sure of the function of these (could be audio low pass,
or could be RF pickup blocking).

You won't get 45dB of gain without transformer coupling, as I don't
think there is enough power supply voltage for that.

Also, noise cancelling headphones normally have an amplifier, so, in
cancelling mode, increase the wanted as well as suppressing unwanted
sound.  Mine are vulnerable to GSM mobile phone signals, so might have
RF pickup problems.  (My interest in Elecraft is to try getting back
into amateur radio, so I haven't used them near amateur transmissions, yet.)

> Also I don't wear my hearing aids with headphones because of feeback. I went
> with behind the ear hearing aids. Maybe a heaphones with larger deeper cups
> would help.

Most hearing aids, including state supplied ones, in the UK, have a "T"
setting, which uses an induction loop pickup, rather than a microphone.
  You can use this with headphones with reasonable field leakage, or
special, silent, ones.  I don't know how sensitive they are to RF pickup.

For some, you can get "shoes" that allow them to be connected to normal
domestic audio equipment.  I'm not sure if these couple acoustically, or
whether they match a connector on the aid.

Theoretically, you could also get headphones with hearing aid type ear
moulds.  In the past, when hearing aids had output transducers that
clipped directly onto the earmould, the clip was the same as used in
professional head sets.  Nowadays, they couple acoustically, with a
plastic tube, so there might not be direct compatibility.
>
> I welcome comments from those who are familiar with the headphone output

Unfortunately, I've not built it far enough to hear more than sidetone yet.


--
David Woolley
Emails are not formal business letters, whatever businesses may want.
RFC1855 says there should be an address here, but, in a world of spam,
that is no longer good advice, as archive address hiding may not work.
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David Woolley-3 wrote

Steve Kallal wrote:
> I have a requirement that my rigs have relatively high audio output wo/
> distortion from the headphone jack. I have a moderate hearing loss, about 45
> db down especially in the speech region. The audiologists calls that

I've had that sort of loss in one ear since childhood and some in the
other, and I did get prescribed an aid as a child, although I haven't
been very good at using it.

>
> I think the best thing about a kit like the K2 is that adding a small audio
> stage internally before the headphone jack doesn't ruin the rig. But I would
> hope that won't be necessary.

As others have said, you could also reduce the series resistors on the
headphone output, although you might need to modify the shunt capacitors
as well; I'm not sure of the function of these (could be audio low pass,
or could be RF pickup blocking).

You won't get 45dB of gain without transformer coupling, as I don't
think there is enough power supply voltage for that.

Also, noise cancelling headphones normally have an amplifier, so, in
cancelling mode, increase the wanted as well as suppressing unwanted
sound.  Mine are vulnerable to GSM mobile phone signals, so might have
RF pickup problems.  (My interest in Elecraft is to try getting back
into amateur radio, so I haven't used them near amateur transmissions, yet.)

> Also I don't wear my hearing aids with headphones because of feeback. I went
> with behind the ear hearing aids. Maybe a heaphones with larger deeper cups
> would help.

Most hearing aids, including state supplied ones, in the UK, have a "T"
setting, which uses an induction loop pickup, rather than a microphone.
  You can use this with headphones with reasonable field leakage, or
special, silent, ones.  I don't know how sensitive they are to RF pickup.

For some, you can get "shoes" that allow them to be connected to normal
domestic audio equipment.  I'm not sure if these couple acoustically, or
whether they match a connector on the aid.

Theoretically, you could also get headphones with hearing aid type ear
moulds.  In the past, when hearing aids had output transducers that
clipped directly onto the earmould, the clip was the same as used in
professional head sets.  Nowadays, they couple acoustically, with a
plastic tube, so there might not be direct compatibility.
>
> I welcome comments from those who are familiar with the headphone output

Unfortunately, I've not built it far enough to hear more than sidetone yet.


--
David Woolley
Emails are not formal business letters, whatever businesses may want.
RFC1855 says there should be an address here, but, in a world of spam,
that is no longer good advice, as archive address hiding may not work.
_______________________________________________
Elecraft mailing list
Post to: [e-mail]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
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