I am working my way through all the discussions around fixed bias versus cathode bias. One aspect that seems clear (or is it?), is that fixed bias gives lower distortion in power amplifiers mainly due to the fact that bias do not change as the voltages in the output tube climb and descend. Am I correct? Ampdog? Handsome? fredeb? Help me if I need to be corrected :comfort:
But when I look at published data of regular output tubes, the lowest THD figures are for cathode bias pairs, usually Ultra Linear connection. I took some screenshots from the TDSL page to illustrate. See below:
6550
KT88
6L6GC
EL34
So the question is: does cathode bias really give lower distortion figures than fixed bias in amplifiers?
But when I look at published data of regular output tubes, the lowest THD figures are for cathode bias pairs, usually Ultra Linear connection. I took some screenshots from the TDSL page to illustrate. See below:
6550
KT88
6L6GC
EL34
So the question is: does cathode bias really give lower distortion figures than fixed bias in amplifiers?
