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Old 6th Jan 2007, 9:07 am   #30
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Default Re: Stereo amp upgrade

Adi.

EL84's do run very hot...too hot to touch after some minutes. However if you are concerned, check the cathode current by measuring the voltage drop across the cathode resistor and apply ohms law. Otherwise just connect a meter in series with the cathode resistor and measure the current directly. If it is a little on the high side, you'll probably need to increase the cathode resistor slightly.

Don't have the characteristics of the EL84 to hand but I think around 45mA should be OK. Remember that measuring the total current through the cathode is a combination of anode AND screen grid current.


Rich.
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