[Elecraft] Poor CW note more testing and a question (rather long-ish...)

[Buck]

My HV shows 74 volts resting and 60 key down

k4ia, Buck
K3s# 11497
Honor Roll  8B DXCC
EasyWayHamBooks.com

On 4/26/2020 4:26 PM, Chuck Chandler wrote:
> After several reports that my CW tone sounded less than perfect I've been
> on a hunt for possible causes.  Looking at the TX waveform on my P3 it does
> look more sausage-shaped than I see in the P3 manual.
> 
> So far I've determined my power supply was a little low and sagging a
> little under full power.  After changing cabling and adjusting the PS, I
> now have 14.2V displayed on the K3 at rest, 13.9 to 14.0V at the 25W level
> used to drive the KPA500, and 13.7 to 13.8V at 100W output.  All that now
> seems as it should be, but the waveform on the P3 is still elongated.
> 
> My KPA500 on a 240V outlet shows HV of 73.5V at rest, 57.3V with 500W
> output.  This is a little on the low side, and I may move the HV tap to
> bring it back up above 60V under load.
> 
> On air testing today with a neighbor I got the report that my CW sounds
> just fine until the amp is in line.  Then it is described as "some kind of
> artifact... like a bell sound... like a delay."  This is consistent with
> the other report I had been getting of a "ringing, bell-like" note to my
> CW.  This is most apparent at 30 wpm, as I would be running in a contest.
> 
> So far, all the reports I have received from fellow amateurs have been
> after a CW Ops weekly contest, during which I usually am running at 30 wpm
> and 500W output.  During rag chews with a bug at 22-25 wpm and 500W nobody
> has said anything bad about the CW note.
> 
> The rig, KAT500 tuner and amp are interconnected via two E850463 Aux
> Interface Cables as shown on page 5 of the KAT500 Manual, Rev. C6
> (3/8/2017).  CW for contesting is generated by N1MM+ via the K3S USB
> interface.  I have a K1EL Winkeyer on order in case the root cause is the
> computer... but that elongated waveform remains the most likely factor to
> resolve.
> 
> My guess is the root cause of all this, power supply issues resolved for
> now, is the elongated waveform I see on the P3.  My rise time seems to be
> at least 3 or 4 times longer than what I see in the ARRL product reviews or
> even in the P3 manual showing an example of a CW waveform.
> 
> I have submitted a contact form at the Elecraft support web page, but its
> the weekend and with them all working from home I wouldn't mind the
> collective wisdom of the group as to any other avenues of investigation.
> 
> And, many thanks for the help so far!
> 
> 73 de Chuck, WS1L
>