[Elecraft] microHAM K3 cables ...

[Don Wilhelm]

Joe,

The Elecraft K3 manual shows pin 6 as 8 volts.  This is *not* 
necessarily the mic element bias.  The bias would be applied directly to 
pin 1 regardless of the use of pin 6.  Remember that the addition of 
bias to the mic AF line is a function of the menu setting rather than an 
added resistor as in the K2.  The voltage at pin 6 will not be turned 
off when the microphone bias is turned off in the menu.

For use with the Elecraft MH2, MD2, and Proset K2, the requirement is 
for a voltage to be added (through a resistor) to the AF signal line.  
That same configuration *should* work for all electret mics that are 
similarly wired and do not have a capacitor in series with the AF line.

Yes, the Elecraft mic pinout is different than Kenwood because Kenwood 
uses pin 5 for +8 volts and Elecraft uses pin 6.  A Kenwood dynamic 
microphone having no preamplifier in the mic head will normally work 
just fine with the Elecraft pinout - but user be aware - you should know 
the pinout of any microphone you plan to connect.  A Heil dynamic mic 
(usually HC4 or HC5 element) with a Kenwood adapter will work fine 
because neither pin 5 nor pin 6 are connected in the adapter.

73,
Don W3FPR

Joe Subich, W4TV wrote:
>> I was under the impression that the K3 was wired the same as 
>> Kenwoods for microphone usage.  However, In checking the Heil 
>> website, and the subsequent link for mike connections, they 
>> show that pin 5 is 8 V., whereas the K3 manual shows that pin 
>> 6 should have 8 V.
>>     
>
> Correct, I had not noticed the error but just compared the 
> Elecraft FAQ vs. the TS-2000 manual and Elecraft show pin 6 
> for bias and pin 5 as "Func" while the TS-2000 manual shows 
> pin 5 for bias and pin 6 as "NC." 
>
> This means that a Kenwood electret mic will not work with the 
> K3 unless the microphone is modified. 
>
>   
>> I'm also curious why my Heil Pro Set headphones seem to have 
>> low output compared to other headphones on various rigs that 
>> I own.   Anybody know what the impedence is for the headphones?
>>     
>
> The original ProSet had 200 Ohm earphone drivers.  A modification 
> replaced those with 32 Ohm units (I think).  The "low output" is 
> due to the reduced output of most amplifiers when driving high 
> impedance loads - Yaesu even includes 10 Ohm resistors in series 
> with the headphones to prevent excess volume in the headphones!  
> Of course, the higher impedance headphones (and series resistance) 
> helps cut down the hum, hiss and distortion. 
>
> 73, 
>
>    ... Joe, W4TV 
>  
>
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