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Original Message
RE: Too low plate R value for a triode ? and CCS substitution?
Posted by Tre' on March 23, 2017 at 13:25:27:
What I was trying to say, and doing a poor job, is this.....
If you keep the plate load resistor high enough as to not substantially increase the HD, the amount of gain reduction from a proper value plate resistor to a less than optimum value plate resistor is so small as to be of no real consequence.
Of course the gain will drop if you load the tube with a vertical load line but why would anyone do that?
I guess I should ask Victor.
"I have just bought a BAT VK5se preamp for good deal.
What I have found is the plate resistor being abnormally low value for the parallel 2 section of 6h30. The plate R of 6h30 per section shown in EH datasheet is 840 ohm per section then parallel 2 section is 420 ohm.However the plate resistor is only 1250 ohm which is less than 3 times of 420 parallel section of 6h30. Is it normal for high priced preamp design?"
So Victor wasn't just "saying" that you can lower the gain of a tube by loading into a vertical load line, Victor is actually "doing" just that.
Tre'