[Amps] Plate modulation from power supply ripple?

[Markku Oksanen]

All
I was simulating (with LTspice) a three phase power supply where the secondary is in star configuration with full wave rectification. You can get also a second voltage from this by connecting to the center of the star, this voltage is half of the full wave rectified voltage and is only half wave rectified (per phase), 3 pulse in stead of 6 pulse for the higher voltage.
It turns out that even relatively high value (tens of uF) filter capacitors would leave some 10% of ripple on the lower voltage.  Now the question is: How much plate modulation this make?  The ripple frequency is 150 Hz and to me this looks like your regular high level, plate modulated AM transmitter.  Why do we not hear this on a typical signal if it is there?

MarkkuWW1C