[Elecraft] headphone impedance

[Vic Rosenthal 4X6GP/K2VCO]

I recently started using an old set of Kenwood HS-5 phones (8 ohm) after 
my cat chewed through the cord on my nice hi-fi phones. I noticed that 
the audio was much louder, I presume a result of the lower impedance. 
I'm even thinking about adding some resistance in series, because the 
audio gain is never past 9 o'clock, even with CONFIG AFG set to LOW.

The Kenwood phones also seem to have a much narrower frequency response 
than 'good' ones. Personally I like this.

73,
Vic, 4X6GP/K2VCO
Rehovot, Israel
http://www.qsl.net/k2vco/


On 28 Dec 2015 22:36, W2RU - Bud Hippisley wrote:
> Perhaps this will help:
>
> Look up the specs on a good home audio amplifier — say, QSC or Crown.
> You’ll find something called “damping factor”, and it’s often 50 or
> more.  Roughly speaking, it’s the ratio of the (loudspeaker) load
> impedance to the internal (source) impedance of the audio amplifier.
> So modern semi-pro and stereophile audio amplifiers are “grossly out
> of specs”, as you put it.
>
> I have a legacy, hernia-inducing McIntosh power amplifier,
> circa-1960s, with output transformers and three taps — for 4-, 8-,
> and 16-ohm loudspeaker loads.  Nothing I’ve owned since then uses
> output transformers or matched loads.  Most audio amplifier designs
> these days are voltage followers.  Most manufacturers don’t attempt
> to match source impedance to load impedance.  Highly damped output
> stages are “good” things to have.
>
> Yes, it’s true that voltage-follower amplifiers deliver more power to
> low-impedance loads than to high-impedance loads.  But if I were to
> follow your line of reasoning to its logical conclusion in the home
> audio arena, I would conclude that 4-ohm speaker systems are
> sonically superior to 16-ohm speaker systems simply because they
> require more output power from the audio amplifier to play my music
> collection.
>
> Does that seem like a reasonable way to choose your stereo system
> loudspeakers?  Or headphones for your K3?
>
> If your 100-ohm (or higher) headphones can’t provide reasonable
> levels of undistorted sound pressure at your ears when your K3 or K3S
> audio gain control is at, say, 9 or 10 o’clock, perhaps it’s time to
> buy a new pair of “cans”.  That’s certainly gotta be cheaper than
> reverting to a 75A-4 with its audio output transformer and 500-ohm
> tap.
>
> Bud, W2RU