The latest update to the 100 Watt 6P45S tube amplifier is about a lot of testing and fault finding that have gone into the tube amplifier. This is to correct noise and hum issues. It is now in a state where the audio amplifier itself is as stable as it will get.
Further improvements lie solely on the power supply, regarding more filtering capacitance. Limiting the inrush current and micro controller supervision and shutdown logic to protect valves and speakers.