25-02-2015, 01:12 PM
Thanks for letting me know - I'm sure they'll stand the test of time...
For info, typical emitter resistors would be 0.1 to 0.47 ohms. In practice, 0.22 is seen most often. Even though these are ridiculously low values, they make a surprising difference to the quiescent current stability, which in turn affects crossover distortion (Douglas Self has written a lot about this - interested folk can find old editions of his book available as PDF downloads - highly recommended!). In addition, such resistors provide a point to monitor the output current for current-limiting purposes. And a point to measure voltage for setting the bias.
Anyway, as you say, it's done pretty well. Mentions of the emitter resistors (or lack thereof) is really a "point of interest" rather than anything more serious
Thanks again,
Mark
For info, typical emitter resistors would be 0.1 to 0.47 ohms. In practice, 0.22 is seen most often. Even though these are ridiculously low values, they make a surprising difference to the quiescent current stability, which in turn affects crossover distortion (Douglas Self has written a lot about this - interested folk can find old editions of his book available as PDF downloads - highly recommended!). In addition, such resistors provide a point to monitor the output current for current-limiting purposes. And a point to measure voltage for setting the bias.
Anyway, as you say, it's done pretty well. Mentions of the emitter resistors (or lack thereof) is really a "point of interest" rather than anything more serious
Thanks again,
Mark
