38
Crossover Distortion in Output
Output Waveform
Distortion Waveform
Crossover
Distortion
Figure A
Refer to Figure A above and note the character of crossover distortion. This is caused by both
halves of the output stage (Q6, Q7 on positive side, and Q8 , Q9 on the negative side) being
turned off right around crossover (crossover from positive drive to negative drive). This actually
takes a small chunk (sometimes only visible in distortion waveform) out of the center of the
output waveform. This also causes some harmonic distortion (Note the curved portions of the
“Distortion Waveform”). Remove input signal to amp and measure DC voltage across emitters
of Q7 and Q8 . Bias adjustment, R16, should allow adjustment from zero volts to well over
10mV. If not proceed to “Bias Reference Test”.
To Next Page
Loading...
