Another Battery Grid Bias Question

Tube DIY Asylum

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

Another question about battery grid bias. Following the advice from my earlier post, I switched from battery cathode bias to battery grid bias on my 27 - 6A5G amp. I connected the negative of a "9 volt" lithium to the bottom of a 100k volume pot. On Eli's recommendation I added a resistor from the grid to the negative of the battery as a safety measure in case the pot became intermittent and lost its connection to the battery. The actual, measured, resistance of the pair was about 82k. Later I added a 150 ohm resistor to the cathode, so I guess it's actually combination bias.
Since the 27 has such a low gain the amp is not real loud, although it's quite usable. While running it (on the bench) I always had the volume pot all the way up. I decided to eliminate the volume pot and, possibly, use a preamp to either get more or less volume.
If no volume pot is used, should I connect the battery negative directly to the grid or put a resistor between the battery and the grid? If a resistor is used, what value should be used?

Edits: 09/14/16

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Topic - Another Battery Grid Bias Question - FlaCharlie 16:27:20 09/14/16 (2)

RE: Another Battery Grid Bias Question - Eli Duttman 16:50:51 09/14/16 (1)

RE: Another Battery Grid Bias Question - FlaCharlie 17:35:22 09/14/16 (0)

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