[Elecraft] Headphone jack impedance

[Don Wilhelm]

Kevin,

The impedance does not matter much.  What is important with ear buds is 
the SPL rating - the higher the number, the more response you will get 
from them.

Where impedance matters is only in low impedance speaker connections. 
For instance the K2 internal speaker is a 4 ohm impedance.  If you 
connect an 8 ohm speaker to the EXT SPKR jack, you may have inadequate 
audio because the audio amp cannot put enough power into an 8 ohm load.

Headphones OTOH tend to be higher impedance devices, and the voltage 
produced by the audio amplifier will be the determining factor.  The K2 
has limited audio (by design) because the audio amplifier is typically 
the culprit for receive current drain.  The K2 was designed for QRP 
portable operation with low receive current drain.

73,
Don W3FPR

On 7/21/2018 10:39 PM, kevinr wrote:
> I am just starting my search for a good set of ear buds to replace those 
> I'm using.  Is there a standard headphone jack output impedance for the 
> family of K2, K1, KX1, K3, KX3, and KX2 transceivers?  I plan to buy a 
> set of head phones or ear buds and want them to be the best match.  I 
> know I could find all this data by opening and doing a ctrl-f on all the 
> manuals but I'm lazy.  Or is it more efficient?
>