[Elecraft] K3 and Expert Amp

[Don Wilhelm]

Gary,

SPE has some misconception that their ALC is fast enough that the 
amplifier will not be overdriven - they do instruct the user to set the 
drive power to maximum and let the amplifier control the drive.

That just does not make sense to me - by the time the amplifier detects 
that it is being overdriven, the distortion has already occurred, and 
then it takes a finite length of time for the amp to increase the ALC 
and throttle back the driving power.  I just don't understand how that 
can work in either zero or negative time to prevent distortion.

I would suggest you drive the SPE amps just like any other - adjust the 
drive power to produce the desired power output on each band (yes, the 
K3 will remember the drive power on a per band basis). That way, the 
amplifier is never driven into the ALC region, and no distortion occurs.

The ALC line can be connected just in case there is some fault - the 
amplifier can reduce the drive level to protect itself.

73,
Don W3FPR

On 9/21/2012 12:37 PM, Gary Slagel wrote:
>   I'm looking at the SPE Expert Amp 1K-FA.  The SPE amps both recommend using an ALC connection to automatically control the radio's output power thus preventing amplifier overdrive.
>
> I talked to an SPE rep and I understood him to say that I couldn't use the ALC connection with a K3 and there was an alternative way to allow the SPE to control the K3 output power by manually configuring the SPE to set the K3 output power on a band by band basis.  I looked at the SPE manual and it outlines a method to set up a flex-radio that does not have the ALC connection but doesn't talk about the K3.  I assume the k3 setup would be the same as for the flex-radio.
>
> Does anyone have experience with setting this up with the K3 and SPE 1K-FA.  Or, experience using the K3 ext ALC with and SPE?
>
>