[TenTec] 565 Low level audio on headphones

[Jim Brown]

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