High gain DC amplifier generally being used to amplify small signal. When crystal transistor or DC amplifier being soldered on PCB Board, thermocouple will be formed between copper layer and component lead, therefore will occur different AC voltage, it will has interference signal against amplifier. In order to keep the minimum temperature fluctuation rate around DC amplifier INPUT point, and remain the balance, we suggest to separate INPUT point with part to avoid the influence caused by air flow.