And yes it is possible to use solid state diodes only. But you have to be careful and make sure the B+ voltage doesn't creep up excessively and become a concern for the filter capacitor's working voltage margin. Modern Dynaco type amps usually have a lot of extra capacitance so inrush current will be large and you may pop a fuse occasionally. And a standby switch or a relay board is mandatory with solid state. Weber makes a copper cap with diodes only (no series power resistor or thermistor) if you feel brave. But though you will have a lower impedance power supply using diodes only.
The Weber copper cap WZ68 is a good compromise between actual tube vs straight diode rectification. The WZ68 mimics two GZ34s in parallel netting 1/2 the series resistance and double the current. Works well in circuit meant for a vacuum tube rectifier.
Last edited by arledgsc on Sat Aug 17, 2013 10:05 am; edited 2 times in total