[Elecraft] K2 Optimizations?

[Darrell Bellerive]

Thanks to all who emailed me.

Just to clarify, I will not be replacing any of the Elecraft supplied parts. 
From what I have read Elecraft goes to great lengths to ensure high quality 
components and subsituting those parts with my own would be a recipe for 
disaster. I also will not deviate from the values specified.

As I look at the K2 schematics it seems there would be places where matching 
components would be of benefit. For example R12 on the Front Panel board 
should be as close to the resistances of RP2 as possible to have even 
brightness on the LED array. Since there are five 120 ohm resistors supplied 
with the K2, why not pick the one that is closest to the average resistance 
of RP2 or even the adjacent segment resistor RP2 pins 1 and 10.

The same with R53 and R54 on the RF board. There are four 4.7 ohm resistors 
supplied with the kit, so why not pick the two that are closest to each other 
in resistance?

There are obvious places where matching would seem to be of some benefit, 
however small, but I am wondering about the less obvious. Since my knowledge 
of electronics is somewhat limited, and I don't understand what some 
components purposes are in some circuits, I was hoping that others would help 
me feed my insanity by suggesting other possible but less obvious components 
to match. I will not hold anyone responsible for any psychiatrist bills. :-)

Along this same line, is it possible to match varactor diodes? There are 
eleven 1SV149 varactor diodes supplied with the kit. Matching D29 to D34 in 
the CW IF filter would perhaps be of some value. Then again I look at the 
pair of varactor diodes D21 and D22 in the VFO circuit and I wonder if they 
should be matched? It would also seem that the combination of D23, D24, D25 
and D26 are grouped to provide more capacitance swing (Am I right?) and may 
benefit from diodes that are closer to the edge of their component tolerance. 
Yes?

Yes, I know that I am bordering on insanity, but hey I want to really take my 
time and stretch out the building. Besides the more I learn about my K2 in 
the process the better.

On August 28, 2005 04:25 pm, Darrell Bellerive wrote:
> I'm about to build my second K2. Stupid me, sold the first one. But then
> again I really like building.
>
> Being a perfectionist to the nth degree and an optimization freak, I am
> wondering about component tolerance and matching components. While I
> realize that with the components supplied and following the manual
> instructions will result in a rig that meets all specification, I can't
> help but wonder if I can't get that last little bit of perfection by
> selecting the best component for the job.
>
> I measure each resistor and capacitor before mounting them on the circuit
> boards just to confirm my correct reading of color bands or values. So if I
> have more than one of a certain value component, and if they have slightly
> different values, yet still within the tolerance, then perhaps a particular
> value will work better in one part of the circuit than another. Perhaps
> even some parts of the circuitry will benefit a tiny bit from matched
> components.
>
> Yes, I know that this is taking things to the extreme, but that is my
> perfectionist nature shining through.
>
> So, can anyone think of any circuits of the K2 that would benefit in even
> the slightest way by hand picking a component that is right on it's value
> vs. one that is near the upper or lower tolerance, or visa versa?
>
> 73,
> Darrell

-- 
Darrell Bellerive
Amateur Radio Stations VA7TO and VE7CLA
Grand Forks, British Columbia, Canada