Stereo 4 Amplifier
This is my present stereo amplifier, designed and built in 2000. This
project is unique in that I built two - one for use in my stereo, and
another for use with my Korg keyboard.
I have been steadily improving the design of this amplifier for 25
years. The circuit topology is fully complementary, differential,
cascode, bipolar transistor. It is direct-coupled from input to output
except for one capacitor and a DC servo. It contains two power
supplies: one unregulated supply for the output stage and a second
regulated supply for all other stages. I think this amplifier can hold
its own when compared against commercial high-end audiophile amplifiers.
The design outputs 80 watts per channel into 8 ohms and 160 watts per
channel into 4 ohms. The amplifier contains roughly 500 discrete
components. The semiconductor complement includes 94 bipolar
transistors, 168 diodes, 2 JFETs, and 2 integrated circuits.