[Elecraft] Icom headphones giving trouble?? (K2)

[Don Wilhelm]

Mike,

The Heil microphones labeled "IC" all have electret elements and *all* 
electret elements *do* need a source of bias.

How your K2 microphone configuration header must be configured depends 
on your adapter - in your case, the Heil Kenwood adapter puts mic AF on 
pin 1 and PTT on pin 2 and pins 7 and 8 should be grounded for the 
return path.  In other words, jumper the K2 mic configuration header in 
the K2 straight across for these pins.  See below for how you apply the 
bias - that gets a bit more complicated becasue there are several ways 
to wire the bias in.  I would recommend using a 5.6k resistor - that mic 
element is the same as used in the Elecraft microphones that were 
produced by Heil - the MD2, the older MH2, and the ProSet K2, those 
microphones sork well with a 5.6k bias resistor to 5 volts.

You can make it work just fine by adding a bias resistor from +5 volts 
(on the K2 front panel board) to pin 1 of the mic jack.
BUT, your Kenwood dynamic microphone will not like the bias resistor 
installed, so you need to decide on using one or the other.

73,
Don W3FPR

Michael Harvey wrote:
> I have tried to use my Heil head phones I had for my IC-746 on my K2 
> and they don't seem to work
> with the Heil Kenwood adapter Elecraft said I needed.
>  
> I normally use CW but thought I would play on SSB this morning.
>  
> I have a Kenwood dynamic hand mic (500 ohms) and it works but audio 
> reports aren't great.
> The head phones have always had great audio but I can't seem to get 
> them to work?
>  
> Do these head phones need a powered mic element. They are made for 
> Icom radios and have an IC on the mic boom pivot.
>  
> Any ideas??
>  
>