hi,
about 2 years ago, in the middle of preparing reports, a flash of an idea came to me, i wrote it in a piece of paper and here is what it turned out:
as you can see from the schematics, the preamp uses a hybrid rectifier using MUR240 ss rects and a 6AS7 double triode (say what?) to produce unloaded raw voltage of about 150v dc. A VR105 gas regulator tube is also used.
this is a line preamp using the DHT 1624 power tube, i got those from Gerry for 500 a bottle, you will notice that the output is taken from the screen grid instead of the plate, at an operating point of about 100 volts dc at about 5mA plate current i am very sure that the grid will not complain, it having a rating of 3.5 watts......
some more pics:
right now, there are hum issues brought about by the power transformer not having enough juice to fire up the gas regulator tube under load.....will update once the power transformer is upgraded...
