On 3/15/2013 8:06 PM, Bob McGraw - K4TAX wrote:
Yet impedance is not related to headphone sensitivity, so two factors
must be considered. Thus headphones of lower impedance should by
choice have a higher sensitivity while headphones of higher impedance
can have lower sensitivity values.
Right.
ANY resistor that you add to the headphone circuit, whether in series or
in parallel, will REDUCE the loudness in the headphones.
This goes to show that one doesn't have to spend a hundred bucks or so
for a name-brand headset that works.
Right again. About 10 years ago, I bought an assortment of about five
Plantronics headsets designed for use with cell phones and/or computers
at a hamfest in Milwaukee. Probably a salesman's sample kit. I made
connector adapters so I could use them with my computer (Skype, etc.) or
with my rigs (at that time I owned used TS850, Omni V, IC746, and K2).
All of the mics sounded very good with all of the rigs, but few of the
headsets were even slightly comfortable. These things all were sold for
less than $30 retail.
About a year ago, I studied the el cheapo crap boom mic headsets at
Fry's, with the intent of finding two for use with Skype. I settled on
two different no-name models for which I paid about $30 total. I've also
found some in this class at hamfests. I made computer recordings of all
of the mics, and evaluated the headphones for sound and comfort. ALL of
the mics sounded OK on the computer, and would likely sound very good
with most ham rigs. All were very cheaply made, would easily fall apart
(one already has). As to the headphones -- none sounded very good, and
are varying degrees of uncomfortable to wear. They're fine for Skype,
but I wouldn't consider them for a contest.
The things that are different about the Yamaha CM500 and the Koss
headset that Richards likes are that they are BUILT much better than the
cheapies, the headphones sound much better, and they are FAR more
comfortable. I can't comment on the comfort of ALL Heil headsets, but
the ones I've worn at contest stations when I've been a guest op have
not been very comfortable, and what I've heard on the air is no better
than the far less expensive boom headsets that Bob and I are talking
about. The Heil noise cancelling headsets I've used also had serious RFI
problems. The other big difference with Heil stuff is advertising
propaganda and "mystique." It's the same thing that Bose sells --
"better sound through marketing!" Gullible hams with little technical
background believe that hype and are willing to pay four times the cost
for them. About ten years ago, I bought a used K2, and it came with the
Heil hand mic that Elecraft sold in the $100 range. For some reason I
had to open it up (don't remember why). Inside, I found an el-cheapo
electret element that probably cost Heil no more than a buck, and with a
very flaky mounting method.
73, Jim K9YC
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