[Elecraft] K2 Keying niggle

[jacob chambers]

Cheers;

I have noticed that when keying my K2 with the crystal filter cinched (200 hz-400) and my audio filter ON in either mode 1 or 2 (the K2 analog CW filter) in certain situations I get an annoying pop or "pssst" sound when sending. I have serial no. 2676 QRP K2 that has had the keying mod performed. I normally use 5 watts with a .12 ms transmit/receive delay. i I built the audio filter to spec and it all tested fine. Any ideas on what I could do to mitigate this minor annoyance? 

73;
Jacob K4JQV