[Elecraft] CM-500

[Joe Subich, W4TV]

> I use my headset with my K2, but would like to try it with another
> rig that supplies 10v. To get my other rig voltage down to the 3-4v
> region require about 12 meg ohms in series with the 10volts
> supplied.

An electret does not draw current in the classic sense.  5.6K seems
to be a good value of resistor for almost anything from 5 to 8V but
12K might be safer for your 10-12V.

The "big name" aviation headsets use 33 - 48K resistors for the typical
48V aircraft system.  They tend to not work well with the 3-5V ham and
computer supplies but if they are opened and the resistor removed (or
replaced with a 2K2 depending on whether the equipment already contains
a resistor), they work perfectly well at the lower voltage.

I've always used a rule of thumb of 1K/V for electret mics.

73,

    ... Joe, W4TV


On 3/14/2013 2:45 PM, Dr Ira J Saber wrote:
> GA  Everyone
>
> I hope this has not been answered before, but I could not find my answer
> in the archives, so here goes.
>
> Can anyone tell me how much bias the microphone is able to tolerate?
> Since the battery pack supplies 3v
> dc, I am sure that 4-5 volts probable won't hurt.  But how about 10-12v DC?
>
> I use my headset with my K2, but would like to try it with another rig
> that supplies 10v.  To get my other rig voltage down to the 3-4v region
> require about 12 meg ohms in series with the 10volts supplied.
>
> All of you guys and gals are a great source for info regardless of topic
> and I wish to thank all and any of you who choose to answer my "novice"
> question.  I have learned something in my years on this earth, that if
> you don't ask you do not get any answers.
>
> Thanks again in advance.
>
> 73
>
> Ira    N2IS
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