In PA applications, Neither Peavey nor the punters will be too concerned about optimum bias conditions for low signal levels. Domestic Hi-fi users are another deal altogether. Many will be using large amplifiers at only 1-5W average levels for the sake of domestic harmony, hearing longevity etc. I think they have reason for concern about anything short of perfection around the crossover region.
additional stability of the idle current through the output stage provides a compound darlington topology (Sziklai) - go to post #36 about
http://www.diyaudio.com/forums/pass...erview-schematic-collection-all-models-4.html
this approach is also often to note by amplifier for stages and instruments - i. e. public address applications. The distortion is even low enough without idle current through the compond output stage, because the driver provides arround 20mA to output - dependend from the value of the resistor between base and emitter of parallel mode power BjT devices.
Efficiency is at such adjustment close by such kind of amps in Class D mode.
Last edited:
Both. To be picky, you should include (base resistance / current gain) as well. e.g. if current gain = 100 and you add a 2 Ohm base stopper resistor, that's equivalent to adding an extra 0.02 Ohms of emitter resistance (equivalent in the context of bias calculations).
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.