Power supply question

[catalin gramada]

D5 makes sure that the neon indicator turns off as soon as the standby switch is turned off, rather than gradually dimming.

Thanks, it have sense. Still it have as effect blocking discharging screen grid supply cap in reverse.

[catalin gramada]

Maybe, but might also be related to the standby switching.

How does it sound with the diode?

With diode it sound more articulated and louder. This is my first impression switching an A-B test in my room with diode mounted and strapped then. It seems maybe a bit distorted. All of this are mine subjective impression.
I used 100uF on plate and 32uF on screens. The series diode used before 5H/100 ohm choke was a 1n4007.

The difference in sound with/without diode is effective even at low volume. The voltage 450V. Current through diode at idling 32 mA around.

[catalin gramada]

OK. Forget the choke and let say I use just a series 1k resistor series with reverse protection diode. At idling the screens will be couple of volts under plate voltage. For sure under transients the momentary plate voltage will be under g2 voltage. So what ? Perhaps the screen currents will raise up for a fraction till plate voltage recover but I didn't burned nothing yet. The sound is more articulated, crisp with better dynamic with this reverse protection diode on supply screens.