CITATION 22 is the name of the 80s HARMAN KARDON amplifier that produces up to 200 Watts of audio at 4 Ohm loads with a symmetrical supply voltage of 58VDC.
INFO
Many sources inform that the power amp was launch around 1987 meanwhile still many low power amplifier made by its competitor. ( MANUAL INSTRUCTION )
At that time amplifiers using large power transistors certainly its classified as hi end equipment.
The appearance of the contents in the amplifier is as follows:
CLICK TO ENLARGE
SCHEMATIC DIAGRAM
The picture below is picture of cropped and edited schematic diagram of CITATION 22.
By seeing at the schematic of amplifier section, I can say that this schematic is complicated.
But despite this complexity, the amp did produce the best audio at the time.
The preamp of this power circuit is using a differential amplifier system, but it uses 8 transistors for this feature also 4 transistors for the current stabilizer.
Meanwhile, for the function of the voltage amplifier stage, it has to use 7 transistors to process the audio input signal.
Servo BIAS transistors are using 2 transistors.
Driver Amplifier uses the complementary Darlington principle. In other word, commonly referred to as Sziklai.
Power Amplifier uses 4 pairs of power transistors with numbers 2SC3907 and 2SA1516.
NOTE
By using a working voltage for a power amp of 58 VDC, it will be possible for this amplifier to produce power until 302 WRMS at a 4 Ohm load.
The Final Power transistor able of working up to 130 Watts.
( SOURCE ).
Meanwhile if there are 4 pairs of power transistors, the maximum power of these transistors will be reached up to 520 Watts.
