[Elecraft] K3 & Amp - ALC settings

[Gary Smith]

The tubes in my Alpha 77Sx are the expensive 8877 variety and I would 
like to setup the ALC connection between my amplifier and K3 to 
prevent overdriving the amp and to back the K3's power down if there 
is a drive issue affecting the amp. It appears I will need to get an 
ACC connector and use pin 15 to connect from the K3 to the amplifier. 
the amplifier is 30 years old and in the manual it refers to vacuum 
tube transceivers. I don't want to the damage the K3 by hooking it up 
incorrectly and perhaps the information in the manual will help 
answer any questions. The  following is taken directly from the 
manual:

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ALC - ALC may be used with suitably-equipped exciter/transceivers to 
help maintain excitation at a desired maximum level. A negative going 
ALC control voltage appears at the ALC jack when amplifier grid 
current exceeds a preset value determined by adjustment of the ALC 
threshold trimmer potentiometer.

This negative-going ALC is compatible with virtually all popular 
exciter/transceivers using vacuum tube power output stages; some 
newer all-solid-State transceivers utilize positive-going ALC, but 
also incorporate their own adjustable-threshold internal ALC which is 
suitable for excitation control in Lieu of amplifier-generated ALC.

In either event, it is necessary that the ALC threshold control be 
set to provide the desired amplifier plate current meter swing wildly 
exciter Mike gain control is simultaneously adjusted to yield the 
degree of exciter ALC action specified by the exciter manufacturer. 
The two adjustments are somewhat interacting so that several 
iterative re-adjustments may be necessary to achieve desired results. 
Excessive mic gain or ALC sensitivity may result in very low power 
output, ALC "Hang-up", and/or distortion.
---------

Is there anything especially salient in the above that I should be 
aware of before connecting from the ALC RCA connector in the 
amplifier to pin 15 in the Elecraft's ACC connector?

Thanks,

Gary
KA1J