[Elecraft] Elecraft Digest, Vol 73, Issue 37- which headphones for CW work

Fri Jun 4 04:00:23 EDT 2010

I recall reversing the phase of one head phone, with respect to the other, in a high-impedance head-set of 1960s' vintage.
I incorporated a switch into the wiring to achieve apparent CW signal separation under some conditions.

It worked surprisingly well. I have tried the same thing with more modern phones but with less
effect. If I find another pair of S G Brown type F phones or similar,  I will do it again.

73 George,  G4TPV

-----Original Message-----
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Sent: 28 May 2010 17:00
To: elecraft at mailman.qth.net
Subject: Elecraft Digest, Vol 73, Issue 37

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Today's Topics:

   1. K3 Headphones (Doug Turnbull)
   2. Re: ELECRAFT TO TOKYO HY-POWER 2.5 (Phil & Debbie Salas)
   3. Re: K3 Was - Which headphones for stereo cw work? Now - Audio
      Spread Spectrum (Jim Campbell)

----------------------------------------------------------------------

Message: 1
Date: Fri, 28 May 2010 16:32:40 +0100
From: "Doug Turnbull" <turnbull at net1.ie>
Subject: [Elecraft] K3 Headphones
To: <elecraft at mailman.qth.net>
Message-ID: <6F2AA728E5E14CB797E91389A0F63BB5 at DOUG1>
Content-Type: text/plain;	charset="us-ascii"

Sam,

    When this topic was previously discussed I saw mention of Extreme
Isolation EX 29 headphones which provide:

1) Good noise suppression (29 dB or nearly a factor of 1000 at 1000 Hz) so
you can keep the volume down and not hear your station's fans or the TV in
the next room.

2) Comfort and an adjustable padded headband.

3) Exact impedance match for the K3 at 32 Ohms and hence plenty of volume
from the K3. 

4) They are California made and cost $99. 

5) Stereo headphones with built in adapter for the larger phone plug jack
used on the K3 front panel.   The adapter plugs in and then screws home over
the smaller stereo plug attached permanently to the phones.   The plugs
appear to have gold plating, which is a complete waste.
6) They come with a nine foot line cord which I just wrapped around a
toroidal core even though I was not experiencing problems with noise.   They
are also available with a 40 inch long cord.

I purchased a set and am most pleased with them.

     You can look the Extreme Isolation EX-29 Headphones up on Google or go
to http://www.quietheadphones.com/product/ex-29 and order by post for $99.
These headphones are made for musicians to use in groups but I think they
are missing another market.

     I also have the Heil Proset Plus but prefer these cans for CW work.
Both sets of phones have their advantages but for CW the Extreme Isolation
phones are more to my liking.   The EX 29 will be clamped to my ears this
weekend for CQ WPX.

           73 Doug EI2CN

PS EI5DI wrote an article for the NCJ some time back on the subject of
headphones.   He prefers Sony MDR EX71SL ear buds because cans bother his
ears when he is wearing glasses.   I also wear spectacles but mine have a
thin wire frames and are comfortable with headphones.

------------------------------

Message: 2
Date: Fri, 28 May 2010 10:55:54 -0500
From: "Phil & Debbie Salas" <dpsalas at tx.rr.com>
Subject: Re: [Elecraft] ELECRAFT TO TOKYO HY-POWER 2.5
To: <elecraft at mailman.qth.net>
Message-ID: <8C53B5B469444EC6B441D24D018CC986 at OwnerPC>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
	reply-type=original

The THP2.5 uses a regular 15-pin D-connector, whereas the K3 uses the 15-pin 
HD D-connector.  Nothing special needs to be done, other than finding the 
pin outs from the manuals.  The THP 2.5 even has pull-up resistors so early 
K3 radios will drive the band data input just fine (NOT the case with the 
THP 1.5, where you need the K3 pull-up mod).  If you plan on using ALC, you 
do need the K3 negative-going ALC mod if you have an early K3.

Phil - AD5X 

------------------------------

Message: 3
Date: Fri, 28 May 2010 11:50:03 -0400
From: Jim Campbell <jim at w4bqp.net>
Subject: Re: [Elecraft] K3 Was - Which headphones for stereo cw work?
	Now - Audio Spread Spectrum
To: "elecraft at Elecraft List" <elecraft at mailman.qth.net>
Message-ID: <4BFFE62B.4010900 at w4bqp.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

This thread reminded me of something that I read back in I believe the 
'80s. There was a circuit in which the CW audio was spread spatially, 
i.e., the lower frequencies were heard toward your left side while the 
higher frequencies were heard toward the right. The idea was that the 
brain could do a good job of separating closely-spaced CW signals if 
they apparently came from different directions. This would require 
stereo headphones to implement.

With the advent of DSP this might be a mode that Lyle could implement in 
the K3 if there was enough interest and if there was really an advantage 
in this mode.

72,

Jim Campbell - W4BQP

------------------------------

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End of Elecraft Digest, Vol 73, Issue 37
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