To put it short>

I have a Reisong A10 which by now is heavily modified with mods largely based on Skunkie's design. I also replaced the output transformers to new ones from Toroidy which makes a massive improvement.

I wanted to experiment with adding SS rectification instead of using the 5AR4. The goal was to increase the B+ and keep the bias current the same by installing a larger cathode resistor on the EL34.

The result of this is largely improved sound, and I do not know why.

The EL34's run on the same current (about 70ma each) before and after SS rectification.

What I notice in sound: With SS rectification the mudiness in the audio dissappears. As if I can look into the music. The bass has cleared up and is very consistent. High frequency response impoved. I can have very very subtle detail wich are mudded before. I can reproduce this constantly.

Can someone help me understand why this might happen?

I have built my test setup in such a way that I an easily switch between the cathode resistor values needed for SS and Tube rectification. I measure the same voltages as Skunkie does with her Reisong a12 mod, except B+ gets an additional 20 volts by switching to SS rectification.