[Elecraft] KX3: Cleaner audio with Yamaha CM500, also PTT

[Luis V. Romero]

I have several CM500'ds and also a Koss SB40.  The Koss SB40 headset is 
IDENTICAL to the CM500 in design and construction, except in one area:  The 
Mic capsule. The Koss mic capsule is dynamic, not condenser.  It is also 
HORRIBLE!  I believe it is a cheap earphone soldered up for mic duty.  It 
sounds like absolute mud and no amount of eq in the K3 or with my outboard 
equipment made it sound acceptably.

Its so bad, I actually removed it.  The top cover to the Koss mic capsule 
holder is a clamp-on to the flexible goose neck, so its removable... up to a 
point.  The bottom of it is glued on, but I was able to pry it off in one 
piece with patience.  The wires are "potted" into the goose neck in some 
sort of plastic-like gray goo.  This left very little exposed wire after I 
removed the plastic holder and then unsoldered the capsule from the wires.

I replaced the whole kit and caboodle with a mic holder and capsule from a 
broken Heil BM10/DX4. The capsule holder from the BM10 boom fits perfectly 
into the Koss goose neck after some very minor reaming of the hole. This is 
the mic I take to Multi Multi operations that use rigs such as Yaesu 
1000MP's and Orions, which like the DX4 element; Im losing my love of it... 
Its tinny and thin with no presence but boy, does it make the meters jump on 
those old Yaesus! :).  But fewer and fewer of these rigs are out there, so 
the SB40 stays on its hanger in the shack more often than not anymore.  I 
have owned it since 2009.

I seem to be using the CM500 less and less too... I have found a headset 
that I really really like the sound of, both in RX and in TX:  The Audio 
Technica BPHS1.  Its a bit expensive, but it sounds just lovely with its 
flat response dynamic element.  Its way more comfortable than the Heil Elite 
and the new Pro cans.  Its built for sports play-by-play announcing.

I have also used the Audio Technica PRO8Hex boom mic along with some $11 
Skull Candy earbuds I purchased at Target.  This combination works extremely 
well in very noisy environments.  The earbuds seal out most of any outside 
noise and the Pro8HEx mic has really good articulation and great presence. 
I use that mic at trade shows when doing demo artist duty as it is light and 
easy on the head, plus, since only I use it, I keep my germs to myself at 
the demo stations.

The same capsule used on the Pro8HEx is used in the BPHS1, so the sound is 
identical.  However, I must say, Im a dweeb when it comes to micsand 
headsets but, in all seriousness, you cant go wrong with the $55 CM500 for 
K3 use.

Lu Romero - W4LT


> I suspect that the mic in the Koss is an electret, simply because 
> electrets are cheaper than dynamics, and these are cheap products we're 
> talking about. :)  The challenge, of course, is to separate the "good" 
> cheap from the "bad" and "not very good" cheap.
>
> I've not seen the Koss products, so have no opinion as to their quality.
>
> 73, Jim K9YC