I found the specs on the B+ transformer so I would have to do some math to check if it can supply enough current but my first thought is no since I believe the secondary is rated around 120vac@50ma.
If the rating is correct it could work.
But - the result wouldn’t exactly equal that of the original Neumann NG PSU.
With 125 V AC secondary (estimate, as you draw 40 mA instead of the rated 50 mA, and don’t load the 6.3 V windings) you end up at ca. 175 V DC after the rectifier.
This leaves 70 V for RC filtering.
70 V drop appears at 40 mA through a total of 1750 Ohms filter resistors.
You would need ca. 3 times higher uF filter caps, albeit with only 200 V max. voltage.
The exact value for the filter resistors need to be determined empirical, and the open circuit DC voltage needs to be checked to specify the filter caps.