After putting in different resistors to drop the voltage on my B+ and not getting the results I wanted(i.e. too much current still flowing through the EL84 causing a low B+ voltage), I decided I was doing something wrong.
There's this term, "negative grid voltage" that keeps coming up with tube biasing but if you've never done this before, then you're probably like me and have no idea what the hell these people are going on about. Then I read Aiken's explanation of biasing found here. After about the 10th time reading if over, I finally understood what was written for my low wattage, class-A.
Basically, all of your tube voltages are measured with respect to the cathode. So if the cathode has a bias resistor, then that's going to push up positively the voltage at the cathode (with respect to chassis ground) once the current starts flowing. Now if you bring the grid connection (pin 2 on EL84) to the chassis ground, then the voltage at the grid, with respect to the cathode is negative. The more negative the grid, the less anode current will flow.
Brilliant isn't?
Now onto the hum. My layout actually seems pretty quiet. I haven't done enough poking around but the source of the hum seems to be my input jacks. There's something screwed up for sure since the low inputs don't work. Definitely a grounding issue.
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