Kt88 Se

[overdrajv]

Hello!

I am going to build my first amp, and I have some questions to ask.

I googled and found only Mikael Abdellahs and related ultralinear connected amps using KT88 in single ended, but i would need cca 25w of output so I was thinking about pentode operation. I found in svetlana datasheet that with anode at 400V, G2 225V, and anode I 87mA yields 20W output.

Now the question is how to get constant G2 voltage from PT?
Idle current of G2 is 4mA and 18mA at max signal. So if I lower the voltage from B+ cca 400V to 225V with resistor ther will be great differences in voltage between 0 and max signal. Should I ask my PT manufacturer to add extra taps for lower voltage?

Can I get make this amp working at 440V at anode with cathode bias cca -20 V so voltage across the tube is 420V and higher G2 Voltage so the anode current is 100mA. That would give 42W plate dissipation and probably 24W output?

Thanks!

Miha