[Elecraft] Yamaha CM-500 (was Heil Elite thread)

[Dave Hachadorian]

> what impedance is the headphone jack on  the k3?


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>From Lyle on 6/28/2010:

The LM4811 headphone amplifier provides maximum power transfer 
into a 16 ohm load (105 mW), and 70mW into a 32 ohm load.  As
you increase the load impedance, the headphone driver becomes
voltage limited.  If you reduce the impedance too much, it
will become current limited. There are 8.2 ohm resistors in
series with left and right channel outputs of the LM4811 and
the front panel headphone jack, and another pair of 8.2
ohm resistors in series from the LM4811 to the rear panel 
headphone jack.  The resistors protect the headphone amplifier
from short circuits, and also reduce the effect of reduced
output in one set of headphones if another set is plugged
into the other headphone jack.

73,

Lyle KK7P
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