[Elecraft] KI6WX modes for the KSB2 ?

[Mark J. Dulcey]

Jeff Burns wrote:

> First the simple one. I have a whole box of parts marked "2N2222". Are these
> equivalent to the PN2222? If not, what is the difference? It would be nice
> to know for future reference.

The 2N2222 is a general-purpose NPN transistor in a metal can. The 
PN2222 and MPS2222 are similar transistors in a plastic TO-92 package; 
similar characteristics, but less power dissipation because of the 
higher thermal resistance of the plastic package. The metal-can 
transistors are better for high-power applications, such as the QRP 
transmitters where they are used as final output stages. On the other 
hand, the plastic-body parts are better when you're going to install 
them in a place where the metal can could cause a short circuit. For 
example, a metal-can 2N2222 would not be suitable for the 2nd XFIL mod 
for the K2, and I don't think it would work for the KI6WX mod for the 
KSB2 for the same reason.

> As I read John's notes the "KSB2 Increased Gain Modification" is appropriate
> for my microphone, but I should leave R2 as I have it and skip the "KSB2
> Reduced Intermodulation Distortion Modification." Is this correct? Would it
> be better to do the "KSB2 Reduced Intermodulation Distortion Modification"
> and add a pre-amp to my microphone if the drive is insufficient? I have had
> the parts for a pre-amp in an envelope for almost 2 years.

My reading is different. As I understand it, the reduced IMD mod is 
ALWAYS a good idea, as it will improve the spectral purity of your 
signal. You then may also need the increased gain mod, depending on the 
microphone you plan to use. Adding the preamp to your microphone would 
be a reasonable alternative to the increased gain mod.