Two keys to a good tube based CF tho. High transconductance tubes and a stiff under lip. Try sim a CCS in the bottom instead of a resistor that steals your voltages. Or a proper inductor. Will save you voltages and give you the oomf. An active CSS is about the same as a large inductor and as a very large cathode resistor. Just that your resistor has to be in the Mohm class to compare and THAT would steal some voltages.
You're right, I'll try it on actual gain version on anode instead of the resistor and in CF version too.
I'm still waiting for Lr8 but I've two dn2540 in my hand...
Dear friends last evening tried ccs based on dn2540 and lm317 as expected i save more voltage on anode but i tried various fixed current bias among 16 and 23 mA, the sound to my ear was not so exciting like ehat i listen whit simple resistor so i rool back.
Did you experienced the same or i done something wrong?
Did you experienced the same or i done something wrong?
A short update, I put the CCS I've built for anode load after regulator and before anode resistors configuring it for 40 mA (actually I mesured a 14 mA on cathode) to give current to both andoes, It run quiet and fresh and I gain, at my ear, more "black" on musicless parts loosing about 6 volts.
I leave it and in next days I go to lessen better, do you have contraindications or suggestions about?
thanks for any answer
I leave it and in next days I go to lessen better, do you have contraindications or suggestions about?
thanks for any answer
Salas, how does one determine the screen resistor value? I was looking at a 6v6 version of the musical machine and he used 330 ohms plus a Schottky diode. His explanation was that the diode was intended to make the resistor "disappear". Thanks ahead of time.
I generally use the lowest value I can avoid oscillation with
A short update, I put the CCS I've built for anode load after regulator and before anode resistors configuring it for 40 mA (actually I mesured a 14 mA on cathode) to give current to both andoes, It run quiet and fresh and I gain, at my ear, more "black" on musicless parts loosing about 6 volts.
I leave it and in next days I go to lessen better, do you have contraindications or suggestions about?
thanks for any answer
Since it works well in practice, no contradictions
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