[CQ-Contest] Yamaha CM500

[Jim Brown]

On Mon,12/29/2014 7:43 AM, Art Boyars wrote:
> *Note!* * Do not use phantom power.

Phantom power is the system used by professional BALANCED microphones. 
The Standard is for up to 48V applied equally through resistors in the 
range of 6.8K ohms to pins 2 and the of the XLR connector (the signal 
pair), with negative on pin 1 (the cable shield).  Phantom power is NOT 
compatible with un-balanced electret mics.  The CM500, like virtually 
all ham electret mics, is un-balanced.

> The maximum voltage is 15v which is provided by the included bias adapter.*

The bias adapter is needed only if the radio does not provide it. Nearly 
all rigs manufactured in the last 40 years have DC in the range of 8V on 
one pin of the mic connector. That 8V can be used to bias the mic by 
adding a resistor in the range of 5k ohms between that 8V and the Mic 
Audio pin (the tip of the CM500 plug). Bias current is tiny, so a low 
wattage resistor can be used and made to fit in the connector adapter 
that you make to mate the 1/8-in CM500 plug to your radio's mic input. 
If you are lucky enough to be using a K3, the CM500 plugs straight into 
the rear panel mic and headphone jacks, and there is a software switch 
to turn on bias.

73, Jim K9YC
>
> So, do you need the Syba (or whatever) external box to get the DC, or does
> the CM500 come with an adapter (and the Syba is just for those other
> functions that Rich mentioned)?