#### matttornado

##### Well-Known Member

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So normally I would calculate bias current by dividing the tube power rating by plate voltage and then taking 60 -70% of that for adjusting the current. That works for 50 & 100 watt amps but what about 40 watt amps?

Do we rate the power of the tube as 20 watts instead of 25 when doing the calculation?

I realize I might get drilled for asking this and some may say I have no idea what I'm talking about but I'm asking anyway.

Right out of the box, my 40 watt DSL was adjusted to 32mA with a plate voltage of 430 volts.

That sounds about right, right?