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previous: T.B. Well, I'll try this one more time. ... -- 7/16/2000 11:30 PM

Re: Signal grid resitors values & output tube distortion???

7/17/2000 11:03 PM
Stephen Conner	Re: Signal grid resitors values & output tube distortion??? Actually the value of that grid resistor is a compromise between two things. For maximum drive to the output tube grid, it should be as high as possible. But, to soak up grid current and prevent thermal runaway, which can destroy the power tubes, it should be as low as possible. This is especially important if you're driving the tubes hard and causing them to heat more. That's why you're advised to swap the 220K for a 100K. With tubes like EL34s, you will still have enough signal left to push them right into hard clipping. Steve C.

7/17/2000 11:03 PM

Stephen Conner

Re: Signal grid resitors values & output tube distortion???

Actually the value of that grid resistor is a compromise between two things. For maximum drive to the output tube grid, it should be as high as possible.

But, to soak up grid current and prevent thermal runaway, which can destroy the power tubes, it should be as low as possible. This is especially important if you're driving the tubes hard and causing them to heat more. That's why you're advised to swap the 220K for a 100K. With tubes like EL34s, you will still have enough signal left to push them right into hard clipping.

Steve C.