Leave filament CT open?

Tube DIY Asylum

Do It Yourself (DIY) paradise for tube and SET project builders.

If I'm changing from a single cathode resistor connected to the filament CT to 4 individual resistors each connected to the filament pins in my ST-70/6B4G, do I leave the CT open? Or do I connect it through a cap to ground? The Pete Millett amp doesn't show a CT, so I'm otherwise assuming I leave it open.
What is the purpose of the 1k resistor between the coupling cap and the grid of the 6B4G in the Millett schematic? Is that necessary or just part of that specific driver? My Curcio board goes directly from cap to grid, but of course is a very different design.
And for those of you that have followed and helped me along the way with this, I'm changing the grid leaks to 220k, and maybe lower. And I'm still not sure all of the tubes are good since one channel slowly drops out after about 10 minutes and it follows a specific 6B4G. This one tube is probably the source of all my current troubles, although I may have had a role in killing the tube with my initial problems.

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Topic - Leave filament CT open? - zacster 11:16:06 02/04/06 (2)

I left mine open and - CharleyW 15:34:37 02/04/06 (1)

Re: I left mine open and - zacster 17:35:13 02/04/06 (0)

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