I'm currently working on a dentron MLA-2500, one of those weekend lazy kind of projects. The dentron has an alc circuit but the voltages are way to high for my icom rig, so, I want to replace the ALC circuit with something that would be more compatible. even if I voltage divided it, or used a zener to limit the voltage, the idea of connecting my transceiver up to something capable of -100 volts or more is not a risk I care to take. Id rather make something appropriate. with that in mind, i am trying to find good writeups on how an alc in a tube amplifier should behave and the proper interactions between the radio and the amp. unfortunately, I am finding some conflicting writeups and various alc designs which don't mesh with each other on how they would behave. also, I have yet to find a curve of the alc output versus drive examples. from what I gather though, as a rough theory, it should have a fairly fast attack and a slow decay. but beyond that, its not clear at what point getting close to an amplifiers peak desired output should the alc voltage start to increase. is it also a time domain driven though, the longer the drive is too high, the voltage keeps increasing until it reaches max or the level drops to an acceptable leveel?? not sure... id love to learn more about this topic, with some accurate information. the goal at the end of the day would be to design my own replacement ALC circuit.