Is this transformer saturation? (pictures inside)

[RavenTheMaker]

Derive the slew rate of the wave form as measured in MS, if the rate is not steady to the spline then check or replace caps.

 

[DF96]

Let me see if I get this right (learning curve, etc.). I'm just witnessing the ouput valves going into clipping. The gridcurrent that 'tries' to flow because of this clips the tops of the signal comming from the PI, because it's not suited to sink this current.

Clipping at the anode does not cause grid current, unless there is NFB in which case it might. As a first stab, assume you are dealing with two unrelated phenomena.

Output valves go into clipping when they run out of voltage or current, as I said. Unless the impedance is exactly that for the maximum power, then it will be voltage or current - with exactly the right impedance it will be both at the same time. If you need more current swing then reduce the quiescent current. If you need more voltage swing then increase the quiescent current. As these are opposites, you need to find out which is actually causing the clipping. Alternatively, change the load impedance a little and see what happens.

 

[funk1980]

Ok, I thought since I'm driving the grid past 0V (cathode), grid current was involved. Guess I was wrong(?).
I did some measurements at the anode and it's indeed at it's max voltage swing. I get close to 250Vrms which translates to 353Vp per side. So it seems it was just my noob-nes interpreting things wrong! 🙂. Thanks for helping me understand things better.