[Elecraft] K2 - Resonate noise on audio

[Don Wilhelm]

Jason,

Do you have the KDSP2 installed on that K2?  If so, make certain the 
noise parameters are off - or simply put it into BYPASS.  Note that 
BYPASS does not survive a power cycle.
If you are power cycling the K2, physically remove the KDSP2 and 
complete the audio path with jumpers from J1 pin 1 to J2 pin 1 and from 
J1 pin 2 to J2 pin 2 on the control board.

The denoiser algorithm in the KDSP2 can cause "strange stuff" in the 
audio spectrum display.

Since you are using a CW filter, it is doubtful that the KSB2 option 
could cause what you are seeing (assuming the switching diodes on the 
KSB2 are doing their job).

If the situation persists, look at the audio amp, or drive an external 
audio amp from the RF Board J5 position to see if it is being produced 
in the product detector or the AF amp.  I am guessing you may be seeing 
mixing products generated by the receiver noise mixing with the signal.

73,
Don W3FPR

On 3/21/2014 10:09 AM, Jason V wrote:
> Quick update.
> All the filter crystals on the RF and KSB2 have insulators installed.
> The KSB2 was removed (jumpers installed across W2 & W3 and C167 populated)
> and the noise is still present.
>
>