I vote for making the PA output transformer primary winding centertapped,
and feeding Vcc into that center tap instead of using the two chokes from Vcc to the drains.
When using LTSpice to simulate it takes a long time for the current through the chokes to ramp up,
and thus a lot of lost time to simulate.? The action when feeding from the centertap is instantaneous.
Almost equivalent is using a separate centertapped inductor to feed power as done on the wa2eby amp.
Has the advantage of spreading the load across the two different toroids.
The chokes work.?
The centertapped transformer (or separate centertapped inductor) is simpler, easier to simulate,
and more commonly encountered elsewhere.
Jerry
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On Sun, May 6, 2018 at 06:44 am, K9HZ wrote:
Ashhar¡ see this result too.? The PA output transformer is sub-optimal so some of us have found.? Needs to be 2T:3T and frequency compensated by a cap across the primary.? My simulations show something in the 330-450pf range as optimal for this configuration, but that is through simulations.
?
