Homemade active two-way HI-FI amplifier 02

(2) Power amplifier circuit
    At present, there are many power amplifier integrated circuits that can be called HJ-Fi "fever" level, and some of them peripheral thick film power amplifier integrated circuits
have good cost performance. Combined with the Hi-Fi "fever" grade active RC crossover circuit, it can be said to complement each other, simplicity is supreme,
it can not only give full play to the performance of thick film power amplifier integrated circuits, but also avoid the disadvantages caused by thick film power amplifiers, such as: frequency band Narrow (
compared to discrete circuits). The power is small and the high-frequency characteristics are slightly poor. 6 Therefore, it is very suitable to be used as a power amplifier circuit here. As an amateur "
fever" power amplifier manufacturer, you should try to avoid "high-end" selection of components, not selecting non-precious components; complicating the imitation scheme
, and not using circuits designed by non-famous manufacturers. If an amplifier circuit board is densely filled with
devices from "famous manufacturers and famous brands", and if the layout of the whole machine is not good, it is likely to cause various noises, which will in turn destroy the performance indicators of the Hi-Fi amplifier.
    In contrast, among the thick film power amplifier integrated circuit series, the new "Dahua" brand thick film integrated circuit AMP80W has better low, medium and high
frequency characteristics, and is more suitable for use as a low frequency power amplifier here. 9 The internal final circuit of the film block adopts Insulated gate field effect tubes, therefore,
have the electrical control characteristics of electron tubes. It has high input impedance, low offset voltage (30mV), good mid-point zero potential stability,
high gain (30dB), high power (80W), wide frequency range (10Hz~50kHz), easy installation and no need to install insulation sheets, etc. See Figure 9 for the many advantages
port circuit. 】.
    In contrast, among many series of power amplifier integrated circuits, TDA2050, TDA2040, and
thick film block STK4151 should be used for high-power unit power amplifier circuits. These power amplifier integrated circuits have good high-frequency characteristics, high conversion rates, and low noise. Therefore,
it can meet the requirements of Hi-FJ "fever" level high-frequency power amplifier. In comparison, among these types of power amplifier integrated circuits, TDA2050 and
TDA2040 have slightly better indicators, fewer peripheral circuit components, and easier installation. This article uses TDA2050 as
the power amplifier circuit of the high-frequency unit to make the treble more attractive. TDA2050 is an improved product of TDA2040, and TDA2040 is an improved product of
TDA2030A . Its various indicators are significantly higher than TDA2030A, and the sound quality is incomparable to TDA2030A.
of. Therefore, generally it cannot be replaced by TD2030 or TDA2030A . The applications of TDA 2050 and TDA2030(A)
are exactly the same