[Elecraft] Matched Filter Crystals

[Paul Jensen]

> > This is a major upgrade and would recommend everyone do it.  For the $15
> > cost and 30 minutes of work (with a hakko 808 desoldering tool), this is a
> > no-brainer.  I also removed c180 (as part of the 2cd Xtal mod).
>
> I thought that if you have a recent K2 and KSB2, you already have crystals that are matched as well as the ones in the kit, so it's not useful at all. Perhaps Elecraft can offer an opinion on which serial numbers are likely to be helped by the upgrade, and which ones don't need it.

Bought my K2 in April - #2592.  They fixed this problem in May or June.
What are your chances of getting 14 perfectly matched crystals?  The K2
now has more gain as well - the volume control is at 8 o'clock and the rf
gain at 3 o'clock for room filling sound.

> Checking your filter shape with Spectrogram or similar software may also help. If your filter shapes are already good, regardless of serial number, the upgrade probably isn't called for - although the early crystals weren't matched as carefully, some builders may have gotten a good set by luck of the draw.

Used the Spectrogram both before and after - it definitely has a flatter
passband now.

Thanks to Elecraft for making this fix available.

Paul Jensen
AD5IW