The invention relates to a seven-stringed plucked instrument
desk sound amplification
system and a seven-stringed plucked instrument
desk, the sound amplification
system comprises a
microphone pickup circuit, a balance conversion circuit, a pre-amplification circuit, a post-stage power amplification circuit and a circuit structure with a small
magnification step-by-step amplification, after a
microphone collects an
electric signal, filtering and
noise reduction are carried out, then first-stage small
magnification amplification is carried out, the amplification rate is 10 times, and the first-stage small
magnification amplification is carried out; it is ensured that low level is not lost, high level is not overflowed, and effective collection of the whole range is ensured. After the
signal is buffered, the
signal is amplified at a small magnification of 10 times, so that a certain thrust is applied to the rear stage under the condition of ensuring the integrity of the
signal. The
amplification factor of 4.7 multiplying power is adopted in the last stage of amplification, so that the
amplification factor of 470 times is adopted in the preceding stage in total, the output
voltage amplitude can be effectively improved without
distortion, and finally electro-acoustic conversion is carried out through the power
amplifier circuit so as to achieve the purpose of ancient sound amplification. According to the invention, the
audio frequency is expanded, frame loss or
sonic boom of the
audio frequency is avoided, and teaching training and large-scale playing are facilitated.