[Elecraft] K3: Upgrade or replace

[John via Elecraft]

I am using two K3's in my remote system. If I want to upgrade the syn boards, do I need to do the control radio as well as the remote radio?
Also the remote radio has the sub receiver, which I use very infrequently, remotely. Do I still need to do both boards in that rig?  Thanks. 
John, N0IJ
Sent from my iPhone

On Jul 10, 2015, at 6:18 PM, Wayne Burdick <n6kr at elecraft.com> wrote:

>> 1) modified bias in the speaker amplifier *driver* (not the amp
>>  itself) for improved linearity.  
> 
> The power amp itself has in fact been updated. And there's a new AF driver stage. 
> 
> Wayne
> 
> 
>> 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
>> 
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