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Again looking into a cathode drive, triode power stage amp. Transformer drive, with a grounded grid. I don't want any DC involved in the signal side beyond what is i*R across the IT's secondary.
Anybody got any good tips? Mention wire type and you go into automatic *IGNORE*...LOL
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
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might be useful
Thanks, have not seen that one in a while, but recall the math applied during the initial work I put into this project. Zero bias leaves minimal cathode resistance to up the output impedance, and the HY51A load line delivered by a 10,000 a-a output TX is comparable to the plate resistance.
That 5k individual load is a remarkably linear operating point with +/- 30V applied to the cathode...:) IMO the biggest attraction to the grounded grid is removal of the step-change in load presented by a grid going positive. That the grid also screens the input from plate capacitance is a freebie.
IT will be an S-250-Q, output will be S-265-Q. The driver amp will be an EL84 LTP driving sweep tubes, likely 6CB5A...:) I think I have an S235Q also if a 6k6 a-a load happens to work better...:)
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
I've got a few of those S-265-Q sitting on the shelf!
Well cool, I have 1 ea of S235Q and S250Q; 3.63:1 and 2.44:1 IT's to try. Now we need a driver amp B+ power trans, and a final's B+ trans.
For a breadboard, I have some UTC S-Series power and filter iron, that with a variac on the primary will deliver the ~600V of B+ required. The driver is a straightforward affair, we'd just terminate it with an OPT with a 500R CT secondary...:) Getting more of the one that works best will not be any harder than sourcing those S265's.
cheers,
Douglas
Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.
nice link here is another ausy guy done it with tv tubes years ago. nice info for the budget builders
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