[Elecraft] Yamaha CM500

[Joe Subich, W4TV]

> It's a very old broadcast engineering technique that we both
> remembered. I've used the series capacitor when I wanted to use other
> pro mics with ham rigs that lacked mic EQ, and it worked quite well.

In this case, the value is chosen in conjunction with the shunt
resistor to provide the 16 to 20 dB pad to bring the CM-500 level
down to something more like what Yaesu expects to see.   It provides
a dual function ... both level matching and response shaping.

> The cap is for LF rolloff, not DC blocking (which is not needed).

It's not needed for blocking in Yaesu rigs.  However, some other
manufacturers do not include a blocking capacitor and failing to
include one in a "DC adder" for an electret mic (or FET preamp)
can upset the bias of the rig's mic preamp.

73,

    ... Joe, W4TV

On 11/20/2010 12:35 PM, Jim Brown wrote:
> On 11/19/2010 6:23 PM, Luis V. Romero wrote:
>> These Orions are really bassy.
>
> I understand.  Makes you appreciate the K3 even more -- no need for the
> W2IHY unit, or for external EQ.
>
> Take a look at the simple circuit that Joe, W4TV,  posted yesterday.
> It's a very old broadcast engineering technique that we both remembered.
> I've used the series capacitor when I wanted to use other pro mics with
> ham rigs that lacked mic EQ, and it worked quite well.  You'll see that
> in the Ham Interfacing tutorial that I posted to my website several
> years ago. The cap is for LF rolloff, not DC blocking (which is not
> needed).  The only trick is finding the small cap needed to fit inside
> the connector.
>
> 73, Jim K9YC
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