[Elecraft] K3 Popping noise in headphones??

[Lyle Johnson]

The selection of IIR versus FIR filtering for the narrowest bandwidths 
(50 Hz and 100 Hz) may also have some effect on this.

In general, the K3 and K3S switch to a different filtering algorithm for 
these two bandwidths.  The loading of coefficients and filter settling 
time -- and to some extent the difference in "energy" that may be stored 
in these filters from the last time they were selected and this time -- 
may combine to produce a small artifact during filter selection.

I'll state again that using the Rx EQ to provide additional filtering 
doesn't work.  The K3 creates a single filter that combines the 
bandwidth, center frequency, manual notch *and* RxEQ parameters.  And in 
general it is a good idea to use rx EQ to tailor the audio response 
using cuts away from, rather than boosts of, preferred pitches, 
especially near pitches you are likely to want to monitor in CW 
operation.  The intended purpose of the Rx EQ is to help tailor the 
radio to your speakers or headphones, not to provide selectivity or 
signal enhancement.

73,

Lyle KK7P

> Thanks for the detailed explanation.  I was beginning to wonder when 
> and if someone would advance a valid explanation.
>
>> There will be a slight pop when changing bandwidth between 150 and 100
>> Hz as the K3/K3S disables the RXEQ at bandwidths less than 150 Hz.  The
>> level of the "pop" will be related to the amount of EQ in use *around*
>> *the center of the passband* (e.g., "pitch")...