31-05-2021, 12:52 PM
(30-05-2021, 06:32 AM)Diabolical Artificer Wrote: Why the cathode follower right at the front went unstable I'm not 100% sure. Looking at it yesterday I noticed I'd wired a pot wiper straight to the control grid, that must lower the grid leak resistor or pull the grid to ground, when in actual fact the grid should be at about 80v. I had a diode connected from grid to cathode to keep V low on power up/whilst heaters warm up, maybe this was switching on/off,hence the clicking?
Schematic to follow. Andy.
I must admit that I am still a bit confused. The example you give with the diode between grid and cathode is fairly self explanitory as there is a positive bias path from a potential divider. The same is not present on the front end of the schematic you give? It appears to have no initial positive grid voltage bias. Maybe I am getting the cathode followers mixed up? You are getting there anyway
Tracy
