[Elecraft] Microphone and BFO questions

[Rolf Moberg, OH6KXL]

Hello!

Does somebody have first hand knowledge/experience from the following 
topics? I now there are several modifications to KSB2 to increase gain. 
KI6WX has done a great document how to modify it. It's found in

http://home.pacbell.net/johngreb/modifications_to_the_ksb2.pdf

My K2 has been on the air about one week now. KSB2 module has not been 
built not yet. I have two extra microphones to use with K2. The one is 
well known Yaesu MH-31 with RJ-45 connector in radio end. The other is 
Heil Pro Set Plus headset with normal HC4 and HC5 elements. I'd like to 
use BOTH of them (MH-31 and Heil) since there are situations where hand 
mic is preferred over headset. Heil headset is normal version, not those 
Icom or Elecraft model.

I know there are several modifications to increase gain. My question is:

Is it really required to modify KSB2 to get sufficient gain in recent K2 
versions? My s/n is 4759. Please remember my mics, Heil headset and 
MH-31. Gain should be adjustable enough to get suitable gain in both of 
them.

In what order it would be recommended to continue?
1. Make KSB2 and install it
2. Install 8-pin mic connector MH-31 and do filter adjustments
3. Build adapter to connect Heil headset
4. Finally, to find it's not possible to use these mics with K2 and 
order Elecraft models of headset and hand mic?

Finally. I ordered L31 to extend limited PLL range. I have problem with 
my BFO lower limit. It is 4912.91 kHz now. It _should_ be 4912.7 kHz or 
lower. Does the extending PLL range affect to BFO upper and lower 
frquencies?

At once my BFO range was as it's required. In that time my 4 MHz 
oscillator wasn't calibrated correctly. I'm optimistic that after 
installing new L31 I'll get my PLL range according to specifications. 
And after 4MHz oscillator calibration I have BFO range where it should be.


Rolf Moberg