A1Noise: Hum, crackle, induction noise, white noise and so on
Hum: Refers to the sense of a low voice in listening, monotonous and stable with 50-100 Hz hum.
Crackle: It is intermittent “Snap” ,”Kaka” sound.
Induced noise: it is a complicated components and shrill hum.
White noise: It is the continuous and random "rustling" sound
1）Make sure the source of noise: Judgment the source of noise comes from pre-amp or amp. Take down the signal’s connection plug step by step from the signal source. If noise is significantly reduced or disappeared, that could be judged the noise source.
2). Identification of the noise sources, should be recognized if between the power supply and grid grounding are well, the cabinet and the ground are good, the cable plug is good contacted with the machine, and between the connection wire’ Signal Shielding ground is good. After exclude the factors above, it could be judged the generating noise and need repair by professional maintenance person.
A2Equilibrium upgrade or attenuation is not obvious
It is popular for using dual-channel 15 band and single- channel 31band equalizer, the machine has 6dB and 12dB to selection on or adjustment. But general condition, we adjust to the12dB better. Found it upgrades or attenuation is not obvious, it maybe open 6db, or please select the 12dB status again.