[Elecraft] K3 - 2.73/1.98 Clicks on Power On

[Paul Christensen]

> My K3 clicks a bit when it is powered on (and off too).  It has been there 
> since the beginning - and has not been dependent on any firmware level.

I agree.  I've noticed the same effect since purchase and it has not changed 
in the least with any F/W upgrades.

> is happening.  I sit and wonder whether anything is happening with my 
> stereo equipment when I first power it on, and I don't know if the 
> power-on really worked OK until the 10 second timeout.

That's part of the delay circuit used to deliberately mute the amp until it 
has a chance to stabilize after power-up.  Typically this is done with a 
simple R/C time-delay relay circuit (or pre-packaged time-delay relay).

If the power on/off transients are too annoying, a similar arrangement could 
be used with the K3 -- and the circuit could be built external to the rig. 
It appears the rear panel +12VDC RCA accessory connector is switched with 
power.  That could be used in conjunction with a time-delay relay to mute 
audio for a pre-determined amount of time (e.g., my K3 finishes its boot 
sequence in ~ 5 sec.).  Then a pig-tail could be used between the headphone 
and speaker jacks to a small project box that houses the time-delay relay 
and the two jacks for speaker and headphones.  Upon powering the K3, the 
time-delay relay would hold the audio circuits open for 5 seconds, then 
close the relay -- the same way its done on my Marantz audio amp.

Paul, W9AC