[Elecraft] K3: Upgrade or replace

[Joe Subich, W4TV]

I agree with Jim - for the same reasons.

After updating the synthesizer(s) and replacing the KVX3/KXV3A
with the KXV3B, if one updates the KBPF3 "general coverage"
bandpass filter board(s) and adds the regulator bypass capacitors,
there are only four remaining "performance" upgrades between an
updated K3 and a K3S - all of which are minor:

1) modified bias in the speaker amplifier *driver* (not the amp
    itself) for improved linearity.  This does not affect the power
    output or frequency response.
2) 5/10/15 dB stepping on the *main receiver* attenuator (this
    does not affect the KRX3 which remains at 0/10dB)
3) improved isolation on the main RF board due to a change from
    two to four layer construction.  The difference is probably not
    measurable on the air.
4) a change in RF output devices in the KPA3 - difference TBD.

The other change is the KIO3B which provides the option of an
internal USB interface for radio control and USB CODEC ("sound
card").  A traditional RS-232 interface is more flexible and a
*high quality* external sound card or *well designed* audio
interface *may* provide a somewhat lower noise floor (better
SNR/dynamic range).  Most users will probably not notice a
performance boost unless they are using one of the notoriously
"dirty" (cheap) amateur products.

73,

    ... Joe, W4TV


On 2015-07-10 12:21 PM, Jim Brown wrote:
> On Fri,7/10/2015 6:07 AM, Bill wrote:
>> I am not a DXer or contester - merely a rag chewer on 75 and 40.
>
> For your operating interests, the only thing I would do is upgrade to
> the new synth board. I consider that 90% of the difference between the
> K3 and K3S. I did that, and because 6M is important to me, I also bought
> the new KXV3B to get the new preamp. I had previously been using an
> outboard ARR GasFET preamp.
>
> 73, Jim K9YC