But why is the crossover distortion in the middle with a general resistor, and the crossover distortion with a speaker will run to the top and bottom.
Presumably because of the phase shift between voltage and current that the loudspeaker causes. The crossover distortion occurs where the current crosses zero, with a loudspeaker or any other load that is not purely resistive, that happens at some nonzero voltage.
There's 1.3V or so of dead zone as the circuit isn't biased to class B (its more like class BC). True class B has one transistor starting to conduct when the other stops, though there's a lot of confusion about class B, AB, AB1, AB2 etc - you circuit is definitely not crossing over, its jumping over!
Adding a pair of simple biasing diodes and resistors will have a dramatic improvement of course.
Adding a pair of simple biasing diodes and resistors will have a dramatic improvement of course.
Way easier to drive and much more voltage output using Darlington outputs.
T1/T2 current sources , D1 - D4 mount close to heatsink to thermal track.
D5, D6 Flyback Diodes so output transistors have short circuit current
limit. Good 80 to 90 watts into 4 ohms depending on rail voltage.
Current shown is DC
T1/T2 current sources , D1 - D4 mount close to heatsink to thermal track.
D5, D6 Flyback Diodes so output transistors have short circuit current
limit. Good 80 to 90 watts into 4 ohms depending on rail voltage.
Current shown is DC