[Elecraft] K3 Firmware Rev. 2.76: No AF noise burst; PRE/ATTN independent for sub RX; etc.

[Stewart Baker]

On my K3 there is still quite a loud speaker 'pop' with Power On 
and Off after loading firmware revision 2.76.

Looking at the NS data sheet for the audio amplifier IC shows that 
it has click suppression built in. The length of the suppression 
period is determined by the value of the capacitor on the Bypass 
connection.The value of the bypass capacitor is related to the 
input coupling capacitor.

 On the K3 cct diagram this is shown as a 0.47uF, which suggests a 
10uF be fitted to the Bypass connection to give a click mute 
period of 0.4S. However, the K3 cct diagram shows a 3.3uF fitted, 
which gives only 0.12S.  

Any benefit increasing the value to 10uF ?

73
Stewart G3RXQ
On Tue, 23 Dec 2008 10:37:46 -0800, wayne burdick wrote:
> K3 beta-test firmware revision 2.76 (with DSP rev 1.98) is now
> available. See release notes below.
>
> Please send any problem reports to k3support at elecraft.com. For
> instructions on how to load beta firmware, please see:
>
> http://www.elecraft.com/K3/k3_software.htm
>
> 73,
> Wayne
> N6KR
>
> * * *
>
> MCU 2.76 / DSP 1.98, 12-21-2008
>
> * POWER-ON AF NOISE BURST:  This should now be eliminated.
>
> * DIGIT 2 SWITCH TONE FEEDBACK RESTORED. The '2' key on the 
numeric
> keypad now provides tone feedback when used for numeric entry or 
within
> menu entries. There's no tone when it's used as "REV" (temporary 
A/B VFO
> reverse).
>
> * SSB TX AFTER VFO A/B SWAP: Transmit filter settings are now 
correct
> after any A/B swap, regardless of the modes of VFO A and B. This 
had
> been
> noted by some customers as a problem on power-up, but it could 
occur
> anytime the VFOs were in different modes at the time of an A/B 
swap.
>
> * INDEPENDENT PREAMP AND ATTN FOR SUB RECEIVER: The preamp
> and attenuator settings for the receiver are now independent of 
main.
> On each band, you can set up the sub's preamp/attenuator as 
desired
> using BSET. The sub's preamp/attenuator are separate even in 
diversity
> mode, where you'll often be using a lower-gain antenna for the 
sub
> receiver.
> Note: A second tap of A>B within the 2-second window still 
copies all
> main receiver settings to the sub, including preamp and 
attenuator.
>
> For software developers:
>
> * "FR0" COMMAND (SPLIT CANCEL): Now correctly restores the VFO A 
arrow
> icon.
>
> * CONFIG:KPA3 MENU ENTRY: The parameter for this menu entry is 
now
> accessible via the "MP" command.
>
> * "FA"/"FB" commands and loss of PLL lock: Large FA/FB frequency 
steps
> were, on rare occasion, causing loss of PLL lock. This has been
> corrected.
>
> * Added "PA$" (sub RX preamp) and "RA$" (sub RX attenuator) 
commands.
> This is in conjunction with the sub preamp and attenuator 
settings now
> being independent of main (see above). During BSET, both return 
"?;"
> at present.
>
>
> ---
>
> http://www.elecraft.com
>
>
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