Common Cathode Resistor

[D0Hbert]

I have a push-pull amplifier powered by 2 el84s on each side. Each couple uses a common cathode resistor, of 135ohm 5 watt, bypassed by a 100uf 25watt capacitor. I'm planning on having 1 cathode resistor for each power tube, what resistor value should I use? Is it 270ohm 5 watts?
Another thing, is it better to have separate cathode resistors or shared? Sonically, is there any difference? As far as tube life is concerned, I'm afraid that if one of the 2 tubes is bad, the other tube coupled with it will be worked out the most.
Any suggestions? Thanks

 

[SY]

The answer to your first question is, "yes."

The answer to your second question is, "it depends." If everything is bypassed, there won't be much of a difference assuming the tubes are reasonably well matched.