On Sun, 1 Mar 2009 21:22:12 -0000, John Stringer wrote: >My Linear is the ACOM >1000 which I believe is similar to the Alpha 91. It has no ALC connection.
In looking at the A1000 manual online, it is a grid driven tetrode with a swamping resistor in the grid circuit. Which sounds very similar to the NCL2000. The online manual does not appear to have an actual schematic, but I would think it would be possible to modify the swamping resistor network to attenuate more of the drive power fed to the tube. In fact, I note that the TRI mode switches a 6 dB attenuator into the input circuit - that may be your answer, if you can find a way to switch this attenuator in pemanently. I see that the swamping network is rated at 100 watts, but adjusting the ALC control in the TR7 for this level should be easy. It should also be possible to add ALC to the amplifier using a couple of different methods. I'm surprised that an amplifier of this class and apparent quality does not have ALC. That seems to be an oversight. 73 -Jim -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! "Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime." HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://radiojim.exofire.net http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
