What the heck is bias anyway?

Bias is the power put into a tube to push the electrons across the vacuum in the tube. Too little and the tube is weak, too much bias and the tube may be damaged.
(and for you experts out there, STOP! he wants real simple explanation. not your twelve page essay.)
The real tubes needing a careful watch on bias are power tubes.
Preamp tubes usually can be OK with a fixed bias. And almost never need to be checked for bias.
So you DO have to learn how to adjust the bias IF you are buying a tube amp without any autobias.
Or you will have to pay regular visits to your local tube guru.

I'm biased against tubes, does that count?

Bias is simply the amount that the device is turned on(a % of max current) without signal(music) passing through it.

So it's basically adjusting the current to the tube to make sure the appropriate amount of juice is getting in and out of it. Not too much, and not too little. I think I have it.

Thanks Elizabeth!

Bias is the power put into a tube to push the electrons across the vacuum in the tube.

I hate to keep picking on you; but once again a technical explanation that is just too wrong to ignore. It is sort of, kind of, talking about what is happening but it is in a nutshell... wrong. I don't understand why you continue to jump in offering technical explanations about things you obviously don't completely understand.

It doesn't require a 12 page essay but it does require something that is correct, The following one sentence explanation is correct.

Bias is simply a voltage applied to a tube to control how much current flows when it is idling.

To say "power put into a tube to push the electrons across the vacuum" is flat out wrong. First of all it is not power, it is a voltage; they are not the same thing; and it is the voltage from Plate to Cathode that pushes the electrons through the vacuum not bias; bias controls how much can get through.

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