WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
Building, troubleshooting and testing of these amplifiers should only be
performed by someone who is thoroughly familiar with
the safety precautions around high voltages.
Have been considering using an LED to bias my Raven linestage. Normally, I see either a common cathode resistor to bias the diff pair, or a CCS. Would an LED be just as good an option?
I will require a 2V, 40 mA bias node, so I was planning on paralleling two red LED's. Yes, no ?
An LED is exactly the opposite of what you need. It's an excellent voltage source (i.e., low source impedance) whereas what you need for a diff amp is an excellent current source/sink (i.e., high source Z).
