400+ watts 4Ω CFA input stage with CFP/Sziklai pair output stage Audio Power Amplifier project. скачать в хорошем качестве

400+ watts 4Ω CFA input stage with CFP/Sziklai pair output stage Audio Power Amplifier project.

Project 57 is another Current Feedback Amplifier project. The input stage is identical to previous CFA-based projects, but the output stage is a Complementary Feedback Pair (CFP) or Sziklai pair configured power output stage. The main advantages of this type of circuit configuration are large beta gain and good linearity particularly in audio power amplifier applications. Because of the implemented CFP configuration, the prototype requires only 1.075Vrms of 1KHz sinewave input signal to produce 41.66Vrms into an 8Ω load with ±64VDC power supply rails. This corresponds to a power output of 216.94 watts at 8Ω or 433.89 watts at 4Ω loads. The prototype's measured THD 0.00738%, THD+N 0.00801% and SNR 90.5 dB by a QA400 audio analyzer. The frequency response is almost flat from 20Hz to 20KHz. Four pairs of TO-264 packaged power output transistors FJL4315/FJL4215 or 2SC5200 /2SA1943 are configured as CFP/Sziklai pair arrangement. These popular power transistors are designed for excellent gain linearity in high-fidelity audio power amplifiers. The real kicker of this project is this -the overall output of the amplifier is acquired at the junction of all the collector resistors of the power transistors, Q15 through Q22. Listening with various CD albums, the experience was extraordinary and did not disappoint. The amplifier reproduces very clean, balanced audio quality. The prototype's test results are also very impressive, one of the best!