I'm looking for a tube bias mechanism that has a higher voltage drop and lower impedance than an LED string. Here's what I came up with. Initial testing shows lower overall distortion than LED bias, particularly for 3rd and higher harmonics, and way lower distortion than resistor + cap bias, but a bit of a rising frequency response. There is only a ~.5db rise from 40Hz to 15K, but it is audible as being a little bright. Any thoughts on viability, or issues that might crop up? Or what BJT to use? I might try a mosfet, too, to see if that's any better.