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该机采用两只2SC9013作超音频振荡,平时不会产生啸叫。但一旦2SC9013损坏或偏磁电路被调整后(即爱好者自行调整时)易出现该故障。因为该机采用交流抹音和交流偏磁,爱好者为了达到理想的录音、抹音效果,往往调整超音频电压,使之高于20V,这样使超音频振荡率远高于信号最高频率的6～7倍(一般,中高档收录机偏磁频率在85kHz左右),如此高的频率和电压的信号使其幅射出的电磁对收音机产生机内差拍啸叫。
The machine uses two 2SC9013 for audio frequency oscillation, usually does not produce howling. However, once the 2SC9013 is damaged or the bias circuit is adjusted (that is, when the hobbyist adjusts himself), the fault easily occurs. Because the machine uses AC wiping and AC bias, fans in order to achieve the ideal recording, wiping effect, often adjust the super audio voltage, so that it is higher than 20V, so that the super audio frequency is much higher than the highest frequency of 6 ~ 7 times (in general, high-end tape recorder magnetic bias frequency of 85kHz or so), so high frequency and voltage signals make it radiate the electromagnetic radio on the radio beat howling.