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Tube DIY Asylum Do It Yourself (DIY) paradise for tube and SET project builders. |
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Tube DIY Asylum Do It Yourself (DIY) paradise for tube and SET project builders. |
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In Reply to: Bias posted by Eli Duttman on April 29, 2013 at 12:45:52:
These hens cratchings are awesome, Eli! I'll start schematics for this soon, and I'll start a BOM, too. Thanks for all the tips and the sketches.A few questions:
1. Will much of the El Cheapo LTP CCS topology still work for use with the 6922 as an anode CCS? Would it just stand on "top" of the tube instead of under it? Does it still need any kind of voltage supply? If not, is the "old" B- entry point now the anode connection, and the "old" cathode connection "on top" now the B+ connection? Is the 5KOhm 5W resistor in the B- entry leg still used? Are the bypass capacitors adjacent to that B- entry point still needed?
2. Are the bias trim pots to be added between the bias supply "under" the 47KOhm grid resistors on the OP tubes? Or do the trim pots replace the grid resistors?
3. In targeting ~200VDC on the 6Y6GT plates, would about 210 VDC make sense for a B+ target to allow for the drop in the OPT? At an approximate 60 mA plate current, I would predict a drop of 8 - 10 Volts across each section of the OPT.
4. In the bias supply, your diodes have a curly cathode and look like the Schottky symbol. Is this the type to look for?
5. Is 63VDC okay for the all the 'lytics in the bias multiplier, or is a larger rating needed? Would 35WVDC work for the first two?
Again, thanks,
--Jeff
[Edited wording on questions after looking again at the bias schematic.]
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