(2) AMPLIFICADOR 2R COMPLETO LYNX-v3-0-QAG

Final test
Connect Power wires to both the “Supply to Voltage
Amp” and the “Supply to Output Stage”.
Remember to connect the Input Gnd to Power Gnd.
Connect the Voltage Meter Gnd to Power Gnd, and
power up the amp.
Measure the Voltage across R128 (“tp E” and “tp F”) and adjust the Bias
trimmer R114 according following to set Bias to 50mA:
If R128=0.22R: 10mV, if R128=0.33R: 16mV and if R128=0.47R: 23mV
Then measure across R129 (“tp G” and “tp H”). The readings should be
app. the same.
Check the readings and adjust the Bias trimmer to the above for every 5
min. for 30 minutes. After 30 min. the Bias should have stabilized and
only measure small variations.
If you have an oscilloscope and a function generator, then apply a low
level signal (e.g. 100 mV/1kHz sine wave) across the Input terminals and
observe the output at either “tp F” or “tp H”.
As the amplifier has a gain of app. 25, you should now see a clear 2.5V
sine wave. If you observe any crossover distortion, then adjust the Bias
trimmer R114 until distortion disappears.
Slowly raise the Input Signal level until the amplifier clips, while checking
for abnormal signal handling or oscillation on the output.
Image here
Image here
LYNX v3.0 Power Amplifier by Jan Dupont, Audio Circuit Denmark
www.audio-circuit.dk
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