[Elecraft] K3 QSK

[Mike Scott]

I can duplicate what might be called QSK thumps with high volume settings
and using earphones or speakers. I have the choke change but have not
modified low frequency response with larger caps. I think the thumps come on
key up not key down.
Everything is fine when I have the volume set at a normal level. I begin
hearing thumps at a volume setting of 11 O'Clock.

What I believe I am hearing though is not an artifact but just high band
noise between dits that give an impression of thumps. The high band noise is
being gated by TR switching. I suspect if I didn't live in a high noise
environment I wouldn't here this.

Mike Scott - AE6WA
Tarzana, CA (DM04 / near LA)
NAQCC 3535
K3-100 #508 / KX1  #1311

I sat down in TEST mode and tried all the combinations you mentioned again
and can't produce thumps. I even tried every possible combination of AF/RF
and MON levels with no thump. 

So I'm sri to say obviously something is different between our rigs and
setups, but I can't imagine what. 

The only audio mod involving a change on the main board is to change a
choke, not a cap. It reduces the resistance of the choke to improve the
voltage regulation at the AF Amp. I've made that too. When I said my K3 was
"stock" Elecraft, it does have the Elecraft-approved and documented mods
made while writing the app notes. 

I asked wondering if the capacitor changes some have made to improve the
low-frequency response were making the low frequency 'thumps' stronger and
audible. If you've not done them, we should have similar rigs. 

Ron AC7AC