Hello all. A year ago, I built this amplifier with Common Ground Collector output topology very similar to that used by QSC in one of its model called USA. A friend of mine gave me two boards which he ordered to make in China and he told me they both had an error which he had not been able to find out. After I fixed them, I mounted all the parts and the circuit was supplied with +/-55V.
For the adjustments, I just turned the null trimpot to set Offset voltage to minimum (0V). For Bias, simply turn carefully the bias trimpot until obtaining 80mV in one of the emitter resistors of the driver transistors and 160mV on both emitter resistors.
The amplifiers sounds very good 😀. I uploaded some photos of the amplifiers I made.
For the adjustments, I just turned the null trimpot to set Offset voltage to minimum (0V). For Bias, simply turn carefully the bias trimpot until obtaining 80mV in one of the emitter resistors of the driver transistors and 160mV on both emitter resistors.
The amplifiers sounds very good 😀. I uploaded some photos of the amplifiers I made.
