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previous: M/J Guys, I was noticing th... -- 8/25/1999 10:13 AM

Re: voltage drop?

8/25/1999 12:32 PM
J Fletcher	Re: voltage drop? Well a zener will drop it's rated voltage no matter how much current is drawn through it, while a resistor drops a voltage depending on how much current is drawn through it. Specifically, V=IR, Ohm's law.A zener gives better voltage regulation. The plate current in a Bassman ,for example varies between, approx 70 and 200 ma, so a zener is better suited to the task.The resistors under the cap pan are decoupling resistors in series with the preamp and driver stages, so they don't affect the output tube plate voltage. Unless you're refering to the 220k resistors across the 1st filter cap network.Varying these will have very little effect on the B+ until you get into very low values that will draw excessive current from the power transformer. You don't want to do this...Jerry

8/25/1999 12:32 PM

J Fletcher

Re: voltage drop?

Well a zener will drop it's rated voltage no matter how much current is drawn through it, while a resistor drops a voltage depending on how much current is drawn through it. Specifically, V=IR, Ohm's law.A zener gives better voltage regulation. The plate current in a Bassman ,for example varies between, approx 70 and 200 ma, so a zener is better suited to the task.The resistors under the cap pan are decoupling resistors in series with the preamp and driver stages, so they don't affect the output tube plate voltage. Unless you're refering to the 220k resistors across the 1st filter cap network.Varying these will have very little effect on the B+ until you get into very low values that will draw excessive current from the power transformer. You don't want to do this...Jerry

Replies:

M/J Jerry, I am really a ba... -- 8/26/1999 3:15 AM