In Reply to: Elrog 300B posted by alexz on January 25, 2015 at 11:13:03:
Your numbers sound reasonable based on the tiny information I've seen so far. Pretty clear that mu is a little lower, rp a little higher - gm=mu/rp is more than a little lower (that's the limitation of tungsten) but the operating point stays pretty good with resistor bias in the cathode.
The lower mu means more drive voltage, so driver clipping is possible if the driver does not have much headroom. After the driver, re-suffling the voltage and current relation to make the clipping more symmetrical might add some mW - though as I understand it this should be a very small effect if the amp is resistor biased.
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Follow Ups
- RE: Elrog 300B - Paul Joppa 21:37:56 01/25/15 (0)