Cant you just increase the cathode resistor value to achieve it? Right up into Cathodyne levels? I dont know much about tube design either, but that seems doable -
No, it's talking about "AF amplifier with controlled amplification", i.e. electronic gain control. But you're building a simple fixed gain stage, no grid control voltage is needed.Well, that's a bit unclear to me: "The control voltage on the grid must not be interchanged with the grid bias, which consists of the control voltage augmented by the voltage drop across the cathode resistor."
So it seems I need a negative supply on the grid in addition to the cathode resistor if I understand it correctly?
I could try using the component values for AF use in the datasheet, it should be able to get down to 0.8% distortion but with way too much gain.
@Sorento - "The more negative the grid gets with respect to the cathode the higher the distortion." Really? So there's a sweet spot because certainly if you drive the grid positive...
For pre-amp service Pentode connected plus CCS load will undoubtedly require a cathode follower
g3 to the cathode, as well as some with both g2 and g3 connected to the anode. Not sure what would be best with this tube.……..G3 doesn't really matter in triode mode
Running a pentode into a CCS load makes for ridiculous amounts of gain. I have a little guitar amp running a 18FW6 (like a 6AU6) into a CCS with a pot across the CCS for variable gain. With the pot at max (2 meg) I get gain in the 1000× range. With that kind of voltage gain the tube is highly microphonic.
If you want to play with a CCS, triode wire the tube.
I don't know anything about this particular tube, but the G3 connection often affects the distortion a bit, even in triode. Try it both ways.