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Old 25th May 2021, 9:11 am   #3
Join Date: Feb 2016
Location: Tauranga, New Zealand
Posts: 118
Default Re: Advice on this linestage build

Originally Posted by Robert Gribnau View Post
The second valve misses a grid resistor.

I am afraid that your tone control is not going to work very effectively because the gain of the second valve is only about 20. That gain is used (by feedback) for the tone control. A gain of only 20 is too low to cover the range of the tone controls from the lowest to the highest settings (about - 15 dB to + 15 dB). In the schematic you linked to, the gain of the second valve is about 70.
I wasnt sure if a grid resistor was needed or not on the second tube, the first one didnt have one.

Anyway, as far as gain goes, I thought 25 was going to be too much, If i configure this as a pentode will I be any better off?
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