[HomeBrew] Class B Small Signal Amplifier Question

[Steven Weber]

Class B amplifiers use a push- pull topology, usually with transfromer input 
and output coupling to get the required phase reversal.

Transformerless push pull amps using transistors generally use series 
connected NPN/PNP output transistors, but are biased Class AB to minimise 
cross over distortion. This means that with no input signal, both output 
transistors have some current flowing through them and one or the other 
turns off with larger input signals, depending on which direction the signal 
is going at the time, plus or minus.

A singled ended transistor amp with no base bias would actually be a Class C 
amp. Class C amps are driven with large input signals to put the transistor 
in and out of staturation quickly for the best effiecentcy. With small input 
signals, but with at least enough level to start to turn the transistor on 
will have an output which looks much like a Class A amp.

Steve KD1JV