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:
--------- 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 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
