[Elecraft] Mods to K3

[Joe Subich, W4TV]

> So, Jim, I would recommend the KIO3B. The pin one problems should be
> gone since you don't need the RS232 port and the line out anymore.

The pin 1 problems continue to exist because the return of the line in,
Line out, and rear panel mic jacks are not tied directly to the chassis.
They still follow an indirect path through the jack board, a pin header,
to the KIO3B and through another pin header to the RF board and finally
to the main circuit common/chassis.  Line in/Line out actually "float"
through audio transformers ...

USB does not have a pin 1 problem but that dos not resolve existing
issues with the microphone input or the "pin 1" issues (failure to tie
the signal returns to the chassis *at the jack*) for all of the other
signals that pass through the KIO3B board.

73,

   ... Joe, W4TV


On 12/5/2015 2:18 PM, ab2tc wrote:
> Hi Jim,
>
> Well, I decided to upgrade to the K3S. The old K3 will replace my IC7200 as
> the "to-go" station. The 7200 is more than adequate for my use, but I have
> become so dependent on the panadapter with my K3(which the 7200 cannot
> support) that I decided on the upgrade. The "to-go" station is mostly used
> in the back yard deck on nice summer days.
>
> The new USB port is wonderful. I use it both for control (with HRD) and
> audio. One surprise I got was that the factory setting (010) for the line
> output (yes, that setting affects the USB audio level) was driving the audio
> right into clipping. I had to reduce it to 002 to be comfortably below
> clipping level. The audio is fairly clean:
>
> ab2tc.com/new_k3s_usb.png
>
> There is still some junk around 3.9kHz (it's always there regardless of
> whether there is a signal in the passband or not.)  The test signal is a
> -73dBm signal from the XG3. The radio is in USB mode with passband
> 300-2700Hz.
>
> So, Jim, I would recommend the KIO3B. The pin one problems should be gone
> since you don't need the RS232 port and the line out anymore.
>
> I agree that the new preamp helps a lot on 10m (and undoubtedly on 6m which
> I don't use). I have the S-meter set for "absolute", but it does not yet
> work with new preamp. Hopefully Elecraft will correct that soon.
>
> I am a happy camper with my new K3S.
>
> AB2TC - Knut
>
>
>
> Jim Brown-10 wrote
>> On Sat,12/5/2015 10:12 AM, Cady, Fred wrote:
>>> I've summarized some of my thoughts here:
>>> http://www.ke7x.com/home/guide-to-the-k3/should-i-update-my-k3-with-k3s-parts
>>
>> I've upgraded my K3s with the new synth board and the KXV3B board. You
>> don't need to buy a book to know what I think about it.
>>
>> I found both upgrades quite worthwhile. The synth board makes your
>> signal cleaner and reduces RX phase noise when the band is full of
>> strong signals. It can be a very big deal in contests and with big DX
>> pileups. The new synth board, combined with a mod to the KBPF3, also
>> enables high quality reception below 500 kHz.
>>
>> It's VERY easy to install. Guys running QRQ say that it improves high
>> speed CW significantly (I rarely work above about 34 WPM). If you have
>> the Sub-RX, you must install two of the new boards.
>>
>> The KXV3B includes the new preamp, which helps a lot with weak signals
>> on 12, 10, and 6M. Installation is more of a challenge mechanically,
>> because physical tolerances make it a bit of a "shoehorn job."
>>
>> That's as far as I've gone with upgrades -- I'll upgrade to the new
>> KIO3B only if it corrects the glaring Pin One Problems present in the
>> original KIO3, which I consider the biggest design mistake Elecraft ever
>> made.
>>
>> 73, Jim K9YC
>> <snip>
>
>
>
>
>
> --
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