VK music - Sunvalley Audio Forum
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In Reply to: RE: TRK3488 caps posted by vkung on February 1, 2014 at 08:18:16:
In the video he says that the .1571vdc on the grid of the output tube is the tube's bias voltage.
This is not true.
The bias voltage for the output tube is the difference between the voltage at the cathode of the output tube and the grid.
The .1571vdc represents a grid leakage current of .0000003343 amps of the output tube and is not the bias voltage. .1571/470k ohms = .0000003343amps
All vacuum tubes exhibit some grid leakage current and that's why there is a limit to the size of the grid resistor you can use.
The less grid leakage current a tube has the larger the value of the grid to ground resistor can be without causing problems.
Bad information in a presentation that's is meant to be instructional is one of my pet peeves.
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Topic - TRK3488 caps - SETdude 06:47:09 02/01/14 (7)
- RE: TRK3488 caps - vkung 08:18:16 02/01/14 (6)Follow Ups
- RE: TRK3488 caps - Tre' 18:39:54 08/31/14 (0)