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Old 4th March 2005, 11:33 AM   #1
D0Hbert is offline D0Hbert  Philippines
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Default Common Cathode Resistor

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
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Old 4th March 2005, 12:42 PM   #2
SY is offline SY  United States
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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.
And while they may not be as strong as apes, don't lock eyes with 'em, don't do it. Puts 'em on edge. They might go into berzerker mode; come at you like a whirling dervish, all fists and elbows.
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