[Elecraft] latest K2 serial #?

[Don Wilhelm]

Robert,

Yes, those two mods are old, and apply only to the A level boards (below 
SN 3000).
There have been improvements in the K2 sidetone incorporated into the B 
level boards, and are also included with the A to B mod kit.
The changes added a 47k resistor in series with C24 (R11 for the B level 
boards) and a shielded 82mH inductor across pins 7 and 10 of RP5.
The sidetone is still not a pure sine wave, but it is close if your 
sidetone pitch is between 500 and 700 Hz.

Those old mods would be applicable to unmodified A level boards but 
re-design of the circuits would be required for the B level boards and A 
level boards already modified with the A to B upgrade kit.

73,
Don W3FPR

On 3/22/2016 5:52 PM, Robert G Strickland wrote:
> The dates of the two sites mentioned are pretty old. I imagine that 
> any such mods or similar changes were incorporated in later K2's. Is 
> this the case?