I know. I'm just comparing and investigating for learning purposes, and first step prior prototyping a real circuit.
Further simulations showed me that UL setup has less THD than the simple screen resistor once I increase output power. For 12 W, the simple resistor seems better (which I still find strange) but for 15W, the UL one remains well below 2%, while the "simple" jumps over 5%.
Just the dissipation power in the tubes for the UL setup make me uncertain about if my design is right. As the graphs above show, they never stop conducting even driving the grid hard (without entering in grid current condition)
Further simulations showed me that UL setup has less THD than the simple screen resistor once I increase output power. For 12 W, the simple resistor seems better (which I still find strange) but for 15W, the UL one remains well below 2%, while the "simple" jumps over 5%.
Just the dissipation power in the tubes for the UL setup make me uncertain about if my design is right. As the graphs above show, they never stop conducting even driving the grid hard (without entering in grid current condition)
With the ultralinear connection your screens are at 300V, compared to 250V for the two different pentode connections. You have the same -9.5v bias voltage for all three, with a consequence that bias current is about double for the ultralinear connection (dissipation 18W!). You need more negative bias voltage to bring the current down to match the others.
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