Quote:
Originally Posted by etype2
...The CTC5 had numerous issues with AGC and most of that is due to the fact that the engineers thought that it was a good idea to create the 140 VDC power source from the cathode of the audio output tube. VERY BAD design to mix any two circuits that way. I do not know why they did not just add a 20 watt resistor to the existing 285 volt supply which would have been a better design. It would have been a very robust design compared to making the audio output tube do the work of making the 140 volt supply which caused many problems that were difficult to troubleshoot....
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On the contrary, it seems to me a very good idea to use the output tube to divide down the B+ to 140vdc. It is better than using a dropping resistor because the output tube regulates the supply. A dropping resistor would mean the voltage would vary widely since it would be load current dependent.