Insane power dissipation on EL34 tubes in push-pull power stage
For one thing, you've modeled the transformer incorrectly. If the total primary inductance is 11.3 H, then the inductance of each half is 2.825 H &mdash; 1/4 of the total, not 1/2. Remember, all other things kept equal, inductance is proportional to N2 &mdash; the number of turns squared. Since each half of the winding has half the turns, it has 1/4 the inductance. The rule about inductances in series simply adding only applies when their fields are not coupled.

Fixing this will greatly increase the coupling to the load. Note that the power that you are currently measuring is almost purely reactive &mdash; the current peaks are aligned with the points where the voltage across the transformer is zero. The real power being coupled to the load is negligible in proportion.



Also, it appears that you've specified the secondary inductance as 214.5 H, not mH.



Now that you've fixed the issues mentioned above, I believe there are still problems with the values you're using. Where did you come up with those inductance vallues? I can't find any mention of inductance in any of the Hammond data.

In any case, I'm willing to believe that the primary inductance is on the order of several henries for this type and size of transformer. But the inductance ratio to the secondary should be equal to the impedance ratio (both are proportional to N2), which means that the secondary inductance in your model should be only

$$2.825\text{ H} \frac{8 \Omega}{3300 \Omega} = 6.85\text{ mH}$$

The high (measured) values for secondary inductance listed in the datasheet are the result of second-order effects such as leakage inductance (imperfect coupling), which appears in series with the secondary terminals.