WAD 6550 Kit Cathode Resistor Upgrade

[Revoli]

I am having occasional surge/flash (disconcerting at least|) seems to be in 6550 valves. Possibly rectifier surge? I have not measured anything as yet. Valves should still be ok.... replaced quite recently. I have notes that suggest upgrades discussed in years gone by for rectifier flash over surge resistors to 47R are a good idea. Wondering if this may be sensible....

There are some other outstanding upgrades I think may be worthwhile when I take the lid off including:

1. Upgrade of Cathode resistor on 6550s to 680 Ohm as per attached article from Oct 2001 re changing pin 8 resistor as per attached article (Hi Fi World Magazine I believe).

2. Improving DC Heater Supply. http://www.world-designs.co.uk/forum...ead.php?t=7643 The idea is the same but these amps are built on tag boards so with replacement of the bridge with 4 schottky diodes and a little re-arrangement of the components the following can be achieved (see attachment)


Any ideas/guidance welcome.