I have a Wright 3.5 amplifier driving a tractrix horn with 113db Radian 950PB compression drivers. To reduce the volume versus the other drivers, I currently have a voltage divider (47K from 6SN7 grid pin to input and 100K from 6SN7 grid pin to ground) providing a 32% reduction in voltage. I have recently adjusted the 6SN7 plate and cathode resistors and have them where everything is sounding good. The problem is I would like to reduce the volume by increasing the 47K resistor from grid pin to input to be 100K for a 50% reduction in voltage. I understand that a 47K grid stopper will start attenuating high frequencies beyond about 23kh. I have read that a 100k grid stopper will start attenuating high frequencies at about 11kh. My question is whether or not the resistor between the grid and input in a voltage divider is still acting like a grid stopper if both resistors attach to the grid pin. Also, if I change to the 100K resistor will the highs be further attenuated.
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That's a good question whether the grid stopper would still perform its roll. But if you attach the two resistors to the grid directly what you create is a fixed value volume control. The common connection to the grid would be like the wiper. The grid leak should not attach directly to the grid if you want a stopper to do its job properly.
Use the 100k/100k pad first, then a dedicated small stopper directly at the grid.
But the high source impedance is not ideal.
But the high source impedance is not ideal.
Why bother ? Install a volume bot, either a full pot or a adjustment type pot. Then a grid stopper mounted with one end directly on the tube socket. Don't mix the functions !