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In Reply to: RE: TRK3488 caps posted by SETdude on February 01, 2014 at 06:47:09
There are 4 coupling capacitors in TRK-3488 (2 for each side).
They are placed between the driver stage and output stage.
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.
Have Fun and Enjoy the Music
"Still Working the Problem"
O.K. so on each side one cap is between the driver and one between the outout tube? I ask because I was considering using different caps between the stages instead of all one flavor.
I bought an assembled unit and it is an excellent amp. Well worth the $$$.
TRK-3488 is a very good sound amp..
This amp is ready for capacitors rolling.. Did you try VCAP copper?
I have not tried the V-cap copper. The amp presently has Clarity caps in it but I think I will use PIO. Do you still have Vitamin Q's?
yes I have Vitamin-Q 0.1 in stock. $16.00 each
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