
Larger internal impedance rectifier, PS is a little better "damped" (no overshoot or "ringing"), but B+ is just 392V... 
Also, "turn on" is slower with 5V4G - about 10-15 seconds no voltage, then another 10-15 seconds slow rise to max. voltage. With DH 5R4GYB, B+ is "there" in couple of seconds...