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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: 09/14/16Follow Ups:
Yes, a resistor between grid and bias battery is in order. A 100 Kohm part should do the trick, but the 82 Kohm part you already have is probably good enough.
Eli D.
Thanks Eli . . . the 82k was the result of the volume pot (actual resistance ~92k in parallel with an 820k resistor.
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